Putting it in a bigger box with more cooling capacity will always make a much faster computer, so that's not going away anytime soon and someone will always find a way to use 20% more power than is available every time a faster computer is made. A lot of things just come down to how well you can cool something, engines, brakes, lights, computers, batteries... how hard do you want to go and how long do you want to do it often determines the form of things.
My computer fits on my desk as it is so making it smaller gains me nothing and just makes it less useful.
Maybe tower PCs will become slightly more niche again in the future, but they'll always be around for enthusiasts like me.
One employer actually asked if I played war thunder in an interview, which I thought was strange until I remembered these stories.