Indeed! But for every topic one chooses to study deeper, one also has to reject some other topics, simply due to the fact that every person has limited time on earth. Thus, one needs to choose wisely. There’s nothing wrong with spending time on learning the skills needed to do self-hosting. But I don’t believe everyone has the same preferences here. Just as not everyone will learn to brew beer, make furniture, sew clothes, make pottery, build a house, etc etc.
As Chaucer would have it: “The lyf so short, the craft so longe to lerne”
And of course, everything gets changed in version n+1 in the churn-churn-churn world of web software so that the skills one picked up become dated fast unless constantly being refreshed. Not worth it for something that only might be useful if they're lucky.
That's a ridiculous take, because the skills you get through self-hosting are actually marketable afterwards.