some timing-sensitive games such as Clair Obscur (parry) or I Am Your Beast (movement)? sure, they depend on low latency. that said, GeForce Now is, sadly, pretty good nowadays. enough to play a moderately fast paced game such as DEATHLOOP. Ukraine, streaming from Germany. 5 GHz is basically required, but in slower-paced games, on a phone, with 720p streaming, you can get by with 4G.
even games are not really a moat for owning hardware - next Gears with its timing-sensitive reloading mechanic can just get adapted for cloud.
if cloud gaming gets another hype wave for one reason or another, this time I am pretty sure they will lock in a much bigger user base. me personally? still committed to owning my hardware, but I can totally imagine my mother playing some RTS on a GeForce Now-connected tablet and having zero complaints.
it is possible to adapt to input/network lag, sure. I played Doom 3 at 10-15 FPS in 640x480 and Warcraft 3 with 300ms latency, and I enjoyed it at the time, but I don't think I could endure such underwhelming experiences after many years of much better ones.
Clair Obscur was perfectly playable for me through GeForce Now, for what it is worth, even when hitting parry timing. (N = 1, but a datum nonetheless)