It makes some sense to sell out if you're building a product that will at best acquire a tiny sliver of the market, which almost all companies will. But there's at least a few AI companies, like Anthropic, that could potentially balloon towards becoming a Big Tech company. So it makes sense for them to not sell out for the time being.

Just FTR - it's VERY rare for people to come up with more than one winning idea

Once a company gets big off its grand idea, there's little to no chance of it having another big winner, so buying one is best (and its cheaper too, you know it's a good idea, and you don't have to spend so much R&D on it.

Big companies have never built anything new. It goes back decades. before tech companies, it was giants like GE who grew through acquisition after acquisition and eventually imploded from the incompetence blob (which takes a long time to accumulate the damage). The same will happen to the current big tech companies in a few decades.

>you will be acquired.

You say this as if it's a coercive given, when you could just as easily say.. Nope, and continue to see how you compete with some agility. It might fail, but most of the big tech companies currently acquiring smaller companies themselves started small with acquisition offers being rejected along the way. Sure, there's selection bias at work there, but there are also many cases of smaller to mid-size companies that also said no to acquisition and still managed to find their successful niche.

Being acquired is not a given and neither is failure if you do compete in some way with the megacorps.

I see nothing about the current tech landscape that at all distinguishes it from previous landscapes in which smaller companies succeeded AND rejected acquisition.