Interesting question! There are many aspects to look into when answering it.
I'll assume you have played that (very) old game 'Contra' by Konami. Have you not?
People can literally master that game in a week, and complete its levels even with their eyes closed in a month. Meaning, it -- and other such old games -- usually had/have short life-time value.
This is one of the key challenges that game developers are now trying to tackle. They are trying to increase the lifetime value of their games, which would improve their retention rate and, hence, their revenue.
This is why we now have a pool of complicated and difficult games that demand players to return back again and again.
In addition, you should also consider the changing habits and preferences of the players. They don’t want the same boring stories. They want more challenges that are immersive difficult.
(Courtesy: Irish Examiner)
So, the developers have to meet those demands.
The need of the moment is to have video games that are tough.
Now comes the introduction of AI in video games
, which will, admittedly, inevitably outsmart you every time.
But then that doesn’t make playing games "pointless", does it?
Imagine if you're fighting a big guy in real life. You know you'll get smothered, but you would still fight him any way.
In games, even when you know you will get killed, you should play (with a hope) -- because it's challenging and fun.
Besides, you must also consider that developers do not necessarily center their games on AI. They leave many loopholes open for the players to outsmart their enemies and win. Meaning, even with higher difficulty, you still get that room to survive and win.
So, a part of your question "AI is strong enough to kill you every time" isn’t completely right. AI villains or opponents are strong. But there still exist many ways you can defeat them.
No developer would want to create a game where the players will imminently lose. That's not a good business model for them, does it?
They would want to keep the game as challenging as possible. But at the same time, they would want the players to stay hooked without feeling that they will never win.
(Courtesy: Extreme Tech)
In short, to answer your question…
"Will it be pointless to play video games in the future when AI is strong enough to kill you every time"
NO, it's not pointless. It will never be pointless.
In fact, with the graphics and storylines that game developers are introducing, the games would be so engaging and immersive that players wouldn’t even care about the end-result as long they are having fun.
Heck, there are so many gamers
who actually want a villain in a game that cannot be defeated. (And I am saying this not because I have watched SRK's Ra.One! ;))
AI will only make video games more interesting and NOT irrelevant.