The Switch has third party support today ?...

It depends on what you mean by "push the envelope".  To me a game like Untitled Goose Game pushes the envelope a lot more than Red Dead Redemption 2 does.  Goose Game is one of the most original games I've played in several years.  RDR2 is basically more of the same with some improvements.

Switch will get games that push the envelope in that they provide original games or at least games not commonly found on the other two consoles.  Pushing the envelope on graphics?  No Switch games are not going to do that.

Yes let's try to change the wording to mean something that wasn't intended.

Just wanted to point out that your reasoning only makes sense in a world where developers don't like money. Porting to Switch can mean big profits, so they are going to continue porting their games to it. You are also making the handheld the limiting factor when not considering that Nintendo may have console revisions up their sleeve to counter the PS5.

If we are talking about big third party games, then how many has the Switch gotten from this gen? Like 5? Doom, Wolfenstein 2, The Witcher 3.....Fifa 19?...…..NBA 2K19?

Yeah, I don't think it will go down much. They will still get the AA games and indie games.

Something that has changed significantly over the years is we don't see 3rd parties really creating exclusive content. There was a period where developers would even create completely different games for lower spec devices, like PS2 and Wii.

Even at 50+ million units sold, it doesn't look like developers are creating unique content for Switch.

Naturally a lot of content like mostly 2D visuals and indie stuff works on Switch. Based on current trends, developers might design some games to scale easily on Switch. Team Sonic Racing and Crash Team Racing for example really seem like Switch was a focus, but these games can still look much more impressive on other platforms.

Well, probably ps4 and one will keep getting games for a long time.
At least xbox will support one with new games for 2 years. PS4 has a large base and developers wont drop it soon.
Would be the same situation that switch currently is in port receiving for 2 or 3 years at least after ps5/XSX launch.

People who claim Switch's third party support will disappear when PS5/XSX come out act as though it's already getting a ton of current gen AAA games and that it depends on them to sell.

Neither is the case.

Switch isn't going to stop selling when it doesn't get the latest Call of Duty, RDR, GTA, etc, because it's already not getting and those games, and that hasn't stopped it being one of the fastest selling systems in history.

Switch does not need AAA third party support.

Oh don't me wrong, I for one really like that Switch gets games like Doom 2016 and Witcher 3, I just don't think they're a major selling point for most consumers since there are so few of them.

Yes. Obviously the high spec stuff won't be ported to Switch, as the current high spec stuff hasn't either with a few exceptions. A ton of Switch's third-party games are 7th Gen and older ports, as well as indies. Neither of those are technically demanding.
PS5 and Xbox Series X will affect the Switch, but I don't expect a huge Switch drop-off because of them. At least not right away.