With the announcement of the Steam Deck, there are some major concerns that are brought up constantly by Users and the Press.
I want to tackle two of these:
1. "This handheld can't play the most recent AAA Games"
2. "Steam OS is Linux-based most of these games won't run on it."
For the first argument: Unless Steam Deck completely crushes all expectations and digs into the hardcore AAA userbase (questionable, because it is a handheld), it probably caters to the Nintendo and, of course, the current Steam userbase. Nintendo's flagship is the Switch and any game that a Nintendo user is happy with, will be playable on the Deck.
And then there are the current Steam users.
2021 is half-over and only 7 games from this year are in the Top 100 and NONE can be classified as "AAA", only 3 from those 7 as "AA" Rest 4 are Indie.
The 1- to 3-year-old games take a third of the top 100 with 35 games releasing in the last 3 years
The 4- to 10-year bracket is the biggest with over half of the games in it (53)
And lastly, we have 5 Games that are older than 10 years.
I think for most Steam users and the potential Nintendo userbase, the graphical power of the Deck will be fine.
For the second argument:
36 Games in the Top 100 have native Linux Support
42 games are "mostly fine" with Proton (possible fiddling involved)
12 games are blocked because of the Anticheat system they are using. Valve already stated that they try to work with these Games/Developers/Anticheat developers to make it possible to play the game with Proton.
2 are unknown (not enough proton user feedbacks)
and 2 are incompatible with Proton.