Yes, Economics is a key factor for innovation. However it alone is not sufficient. At times you simply need other foundational breakthroughs to happen and they will have to be in sequence, i.e. one breakthrough has to happen and become widespread before work on next one can progress, before you can achieve meaningful progress on the end goal.

It is not like Fusion or Quantum Computing has lacked serious or continuous funding over the last 20-30 years.

Foundational model development is a classic current example. The returns are diminishing significantly, despite the tens of billions each quarter being thrown at the problem.

No other R&D effort in our history has this much resources being allocated to it, perhaps including even the Moon landings.

However the ability to allocate resources has limits. Big tech can spend few hundred billion a year a number that would have been unimaginable even a decade ago, but even they cannot spend few trillion dollars a year.