I don't see them releasing a new console straight after their peak year. We are probably looking at 2020 now, especially with big games on PS4 next year like LOU2 and Ghost of Tsushima, maybe Death Stranding I can't quite remember when that is supposed to release.

What's the bet that it'll be a hybrid lol

Sony is known for releasing big games right into the next ps console launch year. Some examples: 

PS2 US launch October 26 2000. PS1 still got big releases that year like the legend of Dragoon, chrono cross, final fantasy IX, and more. 

PS4 US launch November 15 2013. PS3 got the last of us, Gran Turismo 6, the puppeteer, gta5, tomb raider, bioshock infinite in 2013.

So just because there’s still big games left to come out, doesn’t necessarily mean Sony won’t bring out PS5 as evidenced throughout its history. 

already in one year, can't believe it if i see how many great games are still coming out in the next time for ps4

Vita 2.

I hope this is true because it's exactly what I predicted!

Beginning of 2019 is way too early. We already know that 2018 could be the peak year for the PS4 or close to it. Why would a company launch its new product when the previous one is still at the top? They will more likely wait at least one year for the PS4 sales to slow down a bit, it could be an announcement end of 2019, and a release in 2020 (or even everything in 2020). 

The other question is the games. If the dev kits are being sent out in 2018, not enough games will be ready in 2019. And who would choose to release games on the PS5 when the PS4 is still selling truckloads? And a launch with only multi-gen games isn't ideal. You need everyone, developers included, to know that it's time for the next thing. 2019 surely isn't that time.

Developers will develop one more game for the PS4 or finish their current development, and then start working on the PS5. So one more cycle of games, which should take at least 2 years for the start of the next one. And they will lower the PS4 price even more in 2018 or 2019 to push units out before the next one arrives.

Holidays 2020 is my bet, with maybe a teaser at PSX 2019 and an announcement at E3 2020.

Nope, I don't believe.

Sony wouldn't launch a PS5 next year. The PS4 has too much life in it, still lots of room in terms of price cuts and some its known biggest games haven't arrived yet. Many of their first party devs have only just got out their first games.

I'll say Fall 2020 at the earliest,

That's not likely at all. There's absolutely no reason for Sony to release Playstation 5 in a year.

this

especially if the dev kits just left.... No way 3rd party support will be good enough in less than a year if it's q1 2019...

then again with non native speaker they might talk about it for the first time in a special event in q1 2019 now that'd be plosivle....

then again I'm pretty sure the concept of true generations is seeing its final hours before fading out towards a more PC/phone like model... it's not there yet but while it was unthinkable a few years back, I think it won't take an other 10 years to be there... PS4pro and XBoX are fine exemple of how it could become...

and with AR VR, phone tablet laptop fading the lines, mobile and home console also I wouldn't be surprised if we'd see a big paradigm shift in electronic entertainment in the close future