Food for thought: By consistently following a strategy optimizing and picking the optimal product/service based on cost/benefit, you will end up on the same one as everyone else doing the same thing. From a practical perspective this leads to winner-takes-all and centralization. Whoever is the underdog today becomes the Google or Cloudflare of tomorrow and we're back at square one. From a philosophical perspective, did you really make a choice? Or did "the market" (of which you are also part) decide on your behalf? A healthy market needs at least thousands of mail providers, not 5 or 10.

Obviously same thing goes for basing your pick on brand perception, picking the most popular or recommended one, but without the benefit of knowing you'll actually get the better service.

Can free will exist among economically rational participants in a market? There can be some power in knowing you chose whatever you did based on factors other than cost-performance or popularity. Sometimes the optimal choice can be suboptimal.

And why not self-hosting your inbox? Hard to beat from privacy standpoint. It really doesn't have to be as hard as they say. Even if you don't go full homelab right away: Some providers are accommodating and make it easy to gradually or partially self-host by offering open standard protocols. Others make it really tricky and steer you hard into their app ecosystem. So how straightforward it is to use your own local third-party mail client is a good consideration even if you don't intend to self-host anything else anytime soon.