Honestly I can't say if it's definitely the right course of action, although in the last few years there have been reports of millions of 16-35 year-old Americans leaving Facebook, only to move to Instagram. I do think the ability of these companies to buy their nearest rivals is an antitrust issue that needs addressing, for the health of this relatively new market, if nothing else.

AWS + Amazon doesn’t seem obvious to me; would there be much to gain from breaking up a conglomerate into several businesses, when those separate businesses are in entirely different verticals?

I suppose breaking off AWS might lower Amazon’s ability to subsidize an unprofitable retail business in search of market share, though that is probably a moot point now that Amazon is raising its prices in search of profitability and is likely to stop being the de facto online shopping destination now that other online retailers are also standardizing in two day shipping and easy returns (often easier due to providing return labels in the box).

Might run fewer brick and mortar stores out of business before being forced to sell at a profit.