I don't care so much about the money. I am in the comfortable situation that it doesn't matter if I spend 30, 60 or even 100 Euros for a game. But I'm still not buying at launch anymore for the sole reason that games nowadays are way too often a buggy mess at launch. I don't want to waste my time for something like that. So I wait 2-3 years until the games are patched and in a playable state.

Nintendo is of course the exception. At least for me, I never had any issues with games from Nintendo. So I don't hesitate to pre-order games as soon as they are announced.

I buy very few games at launch, for the simple reason that they rarely function as intended. This has gotten worse with time, the past 5-6 years have been particularly bad in this regard. The price isn't all that important, I've even waited for sales to end so I can purchase Indie titles for full price and support the developer.
I have the same mentality around consoles; I don't buy them right away. I usually wait at least two years or more, kinks get ironed out, the catalogue of games has grown, and services and functioning better all-round.

I agree unless its from a small developer or new IP that really needs the sales. People say they wanna support the the developer but games like spider, zelda and mario are already guaranteed success. Just buy ebay and buyed used keep looking for a newly listed buy it now deal and you will get games for 35$ in mint condition that just came out 3-6 months ago and with updates that fix bugs.

While I do understand what you mean we also need to think a bit about cause and effect. 

Go back in time a bit in a forum like this and find a thread about this and the answers will be simillar. I’ve read about people whining about Nintendo never lowering the price on their games and people mainly buying games when they are on sale for like $15. This goes back way before MTX was the norm. 

And in all honesty if people want even a skin chance for predators MTX to go away the only option is to not buy those games at all. But with the reasoning you are using you are sending a clear signal that MTXs are OK on a for free or discount game. 

I've never bought a single MTX separately, but have waited on the inevitable GotY editions that come with all the content that should have been included originally.  

At the end of the day if developers are going to nickle and dime, so am I.  Fair is fair.  

the Nintedno ports only released because the WiiU failed. I tend to buy Nintendo games at launch because they are worth it and they won't go down in price for years to come. Every other company reduces their prices relatively quickly so those are worth waiting for

I do prefer to play the finished versions of games so agree with that sentiment. Others will like coming back to play something like an expansion but I prefer that extra content to be there during the first playthrough.

Just wanted to add without launch nights. There is no more excitement to buy games at launch

At this point in my life, I am a retro gamer. By the time I get to a game in my backlog, it's a retro game at that point.

If I never purchase another game again and played only the games I currently own in my backlog, I still probably won't be able to play them all in my lifetime. I'd have to quit my job and find someone to fund me to do just that.

With those things in mind plus everything mentioned in the OP, I see no reason to ever buy games at launch. Back in the Wii U days, I felt a sense of obligation to go get games early to show support, but with everything on Switch hitting record sales for its IP and just generally feeling less FOMO as I get older, the only times I feel pressured to get a game is when:
A) A physical copy is on a good sale, so supplies are of limited of course
B) There really is a big benefit to pre-ordering or getting it at launch, like when it comes with physical rewards like an extra controller, posters, etc.
C) It's a tiny IP that the publisher finally remembered exists, and the fanboy in me has to show that support (hi Advanced Wars!)

If I had a time machine, I would send messages to the past to tell myself to wait on so many games that will get a port to a newer console/HD rerelease/series compilation rerelease later. So many games I have yet to play that have gotten enhanced rereleases later, that I'm either like, "Man I'm glad I didn't get this game on ___ a few years ago!", or
"Dang, if I knew it was going to come out on ___, I wouldn't have gotten it for ___!"