That's because they were fucking amazing games. And this comes from a person who thinks MGS 4 suffered with the sames problems Death Strading does but in a even worse level: cheesy dialogues, messy script, stupid moments (I HATED AKIBA WITH A PASSION, almost ruined the game for me). But like Death Stranding too, when the story and characters work, they really really work, and make for some of the most memorable moments in gaming (everything Snake and Liquid related in that game was amazing and i loved it). That's what Kojima gives to you. I accept the bad if i get this level of good too.
As for MGS V, MGS V is another amazing game. Its gameplay is still unmatched in an open world/sandbox-stealh/action game. The amount of different aproaches/ways to play the game are masterfully crafted. Yes, the story is inconclusive and lacks any good direction for the most part, but still talks about interesting ideas like imperialism, pacifism, identity, family, treason, loyalty, etc....It's production values are top notch too and is still one of one of my most played games this gen. And what gives if it does not have a good story??. Zelda BOTW does not have a good story either and nobody cared and received a 97 on metacritic....In fact, because it was a Kojima game, I think MGS V was unfairly trated after launch just because it was not treated like a normal game.
As for the fact that those games received better scores than MGS 3, that probably happened because the original version of MGS 3 had that fixed camera from above a la MGS1-2 that made things way more difficult than necessary, a thing that was fixed with the Subsistance version. Oh, and by the way, MGS 3 is one of my top 5 games ever, with the best story Kojima has written by far. If MGS 4 and MGS V were 9/10 games (like Death Stranding) for me, MGS 3 (Subsistance version of course) is the pure definition of a 10/10.
Those games deserved the 90+ scores...They're classics, even with their faults. And Death Strading should have been treated the same way, i mean like a 90+ scored game.
Well I can only speak from my personal experience, but I played MGS4 after my friends had already played it. And so before starting it, I was curious what I was in for and asked a number of my friends how they would rank the game in the series, and what they thought of it.
What stood out to me was how in every case, they without hesitation ranked it at the bottom, or second to last above MGS2. That in itself isn't necessarily a worrying factor because I don't think any of the previous mainline games were bad. But the lack of hesitation was definitely noteworthy.
But then they coupled that ranking in with rather un-enthusiastic impressions of the game. It seemed alright. And not much more.
And after I played it myself I felt the same way. I'd say I even found it underwhelming for a MGS game. At this point it felt like MGS had 'jumped the shark' to a notable degree. (And perhaps Konami forcing Kojima to constantly work on these games started showing in the games to a degree.)
As I sit here I struggle to think of any new interesting gameplay mechanics in MGS4. The stealth camo was an evolution of the camo outfits from MGS3, but I actually found it more interesting to use certain camo in certain environments rather than having one suit for any occasion.
And they took out the ability to eat a lot of different things (and have very interesting conversations about it with Paramedic, which I miss) as well as the ability to injure and heal specific parts of your body.
Though my biggest gripe with the gameplay was definitely the warzone setting. I felt that the 'Nowhere to run. Nowhere to hide' aspect just did not work well with how they designed that area. (It did work very well in MGSV though, which I'll get to below.) The only memorable thing about that setting for me was how boring it looked (everything was beige) and played.
I did however like the stalking mission that came after, where you follow an agent while trying to listen in on their radio, and stay out of sight while also not losing your target in a new city type setting. But it was very short, so I would have liked to see more of that mechanic in the game.
Later on when you return to a certain familiar location, that was brilliant and nostalgic. And unfortunately also pretty much the only time where I thought MGS4 was a really good game.
As for the story, I won't go into much detail here, but I felt like they made Snake pretty uninteresting. Mostly just just moping about how he's not a hero. Meryl tried to make interesting and meaningful conversations with him, but he just ignored it all. The villains were just mindless soldiers, except for Liquid Ocelot. He was fine. (Although that plays into a criticism I have of MGSV.)
You mentioned how not having a good story isn't necessarily important. And I do agree with you there.
However, there's also a difference between not a good story, and a bad story.
For example, Ocelot.
Ever since MGS1 they established a working relationship lore between Ocelot and Big Boss. So for many years I wondered how they went from being enemies (sort of) to colleagues.
Well, apparently he just... randomly joined. That's it. Definitely not what I expected.
But on top of that, they made him almost completely insignificant. He was essentially just there to keep Miller calm. And it doesn't end there. They inexplicably changed his personality. He went from hot headed and eccentric in MGS3, to extremely calm, mellow and rational in MGSV, back to being hotheaded and eccentric again in MGS1. Wtf?
Was that even Ocelot, or Troy Baker?
Speaking of which, using Kiefer Sutherland for Snake was a really bad decision.
And Snake playing in a puddle of water with Quiet (someone whom he barely knew at that point) is something I did not need to see.
The overall tone and world building in MGSV was just very weird, even for a MGS game. It focused heavily on gruesome elements, which up until that point had been more of an undertone in the previous games. The negatives in the story department stood out like a sore thumb.
The gameplay however I thought was fantastic. I spent a lot of time just trying out fun stuff like taking down helicopters by having Quiet bounce a grenade I threw. It was really fun the whole way. But since everything else was so bad to the point that it bothered me, it wasn't a legendary game for me, and I wouldn't rate it anywhere near MGS3 or 1.
For reference, in the 10th Annual Greatest Games Event, both MGS1 and MGS3 rank extremely high up in my list. But MGS 4 and 5 are not in my top 50 at all, and wouldn't be in my Top 100 even.
I do agree that the adjustable camera in MGS3 Subsistence was a positive, and in some cases necessary fix. But at the same time I didn't think the lack of that feature was a determent to the original version of the game.
Unlike MGS 1, 4 and 5, it didn't have the luxury of being the first entry on the platform. So it wasn't as much of a technical showcase in that sense. But it still managed to impress me on every level.