We've done this in the past. AT&T was broken up into the regional baby bells. Eventually, the baby bells started to get absorbed back into the monolith AT&T again. Nobody stopped it. I assume that the fact that few people use landlines and there are more than one provider of communication services where the AT&T voltron is no longer a monopoly.
The point? Not really sure, but as much as I'm all for breaking up Alphabet, I'm not convinced it will work. I'm willing to give it a go though
Trustbusting is like weeding your garden. It's just a chore that must be done periodically to counteract the natural tendency of markets to degenerate into monopolies. It's not something you do once and then never again, it's something that you have to do regularly, forever, if you want a functioning market.
Your "do regularly" got me thinking. There's only been 2 companies in the US to have been busted up, Standard Oil (1911) and ATT (1984). Microsoft (2000) got close but cut a deal. So yeah, we haven't been tending garden very well