Huh? No. Anyone with relatively deep pockets could easily disrupt Uber right now. Uber's technology is pretty simple and straightforward, and not meaningfully patent-protected. You can do the same tech given six months or so and a decent engineering team.
And Uber's customer-base is price sensitive. You can easily get into this market if you're willing to price compete with Uber.
Now, Uber is very willing to price-compete ferociously. It will absolutely drive you both deep into unprofitability. And Uber has quite a war-chest, and it can push around its smaller competitors this way. But as rich as Uber is, there are plenty of companies that are richer. Way richer. Orders of magnitude richer.
I think that so far, the really big boys have said, "Why do we want to get into a price war with Uber? They'll fight until the last breath, I don't see why we should launch a deeply unprofitable ride-sharing service."
Amazon might do it eventually. They have expertise in operating at high scale, low-margin, and they're big enough to destroy Uber. They also might want to use a ride-sharing service to deliver goods. I think that right now, they've mostly said, "We're unconvinced that there's a real logistics business here, and so we aren't going to get involved."
Google might do it for the data.
I can't see Apple bothering -- it's pretty far outside of their corporate comfort zone. But if, I don't know, Tim Cook gets hit by a bus and their new CEO wants to make major changes, they absolutely COULD do it.
Microsoft could maybe do it in an attempt to create a compelling entry-point to their ecosystem, but it's not very Microsofty.
I don't see that any non-computer companies currently have a reason to try it.