Good question. Big companies participate in incrementalism. Many companies invent one big thing and ride it for decades. Few build new things and succeed. (e.g. Apple). Some try, e.g. Microsoft with Xbox, Meta with VR, but even then often it ends up being billions of lost profits. Innovation often come from small groups of persistent and intelligent people and their first few acquisitions as they succeed. e.g. Microsoft with DOS, Windows and Office. They're still riding it.
The last startup boom began in the mid-2000's (around when Y Combinator began, you can read all about it on Paul's blog), when cloud computing was still new and lowered the cost of creating online businesses. It was also in the wake of the tech bust - a lot of tech employees became unemployed.
My view is, when the layoffs complete, the dust settles and you have millions of tech workers who are willing to accept only equity, with a new technology they can rent for $200 a month from DeepSeek or Anthropic or OpenAI, we may see the green shoots of a new wave of disruption.