Ever calculate the cost of a computer in the 1960s, adjusted for inflation? Training is unfathomably expensive right now. What if a bunch of universities pooled their money? Or a bunch of nations pooled their money? Breakthroughs will eventually happen, optimization will occur, etc.

People questioned whether there could ever be a viable open source operating system, yet Linux has been a viable option for a desktop environment for decades now, and that's not to mention its ubiquitous use as a server or phone OS.

Yes, but have you seen what's happened to hardware improvements over the past 20 years?

From the 1960s to the mid-2000s, every 10 years you'd have a big enough improvement in computing power that you could basically throw out the old computers and replace them with two new ones that were each massive improvements for the same cost (this varied, of course, from hyperbole to massive understatement). We achieved this by shrinking transistors, so we could fit more onto the die. With that, we could dramatically increase clock speeds and the amount of RAM we could cram into a machine

But then we hit the wall of physics. Things haven't stopped improving since ~2015, but they've slowed down so, so much. We've made transistors so small that there's very little more improvement we can get by continuing down that path—they're already seeing serious quantum tunneling effects that need to be adjusted for.

We can no longer assume that we can just powerscale our way out of any computation-cost problem. And breakthroughs, by their very nature, cannot be relied upon—we have no guarantee that there's even a possible way to improve our silicon to scale the way we did before, let alone that it'll be something achievable this decade, or that it'll be cost-effective.

Yes,

You have to start some where. Im guessing, making progress also brings in new ideas how to move further.