I don't believe the lack of capital investment is a problem. There's mind-boggling amounts of capital being wasted on the metaverse and blockchain bubble that could be directed towards building a disruptive competitor to any of these companies' flagship products.
Rather, I see the problem being that any time a viable competitor appears, it just gets acquired so there's no longer any need for the incumbent to compete. Case in point, Instagram actually became the next hot social network after Facebook, but Facebook the company retained relevance and market share by simply buying them rather than competing. Google has also acquired a bunch of more niche search engines over its lifetime (that's a little more subtle in that none of those alone were going to beat Google like Instagram did to Facebook, but by nipping niche search providers in the bud, Google consolidated the market share around its product).