What you note is not as painful a thing to most...But I'll grant you that to some it still is a thing. Here's where owning your own domain name helps avoid falling into this type of trap.
Having your own domain name represents YOUR identity/persona on the web - nay, overall internet in fact. The focus here is on the portion AFTER the @ symbol. Yes, unfortunately for now, owning your own domain - for the purposes of interacting with other instances and people via these federation-type of technologies - also involves the overhead of hosting your own mastodon, gnu social, pleroma, ActivityPub server, etc. But in the future, it could be that the underlying mechanisms could be made much easier and cheaper both to use and to switch/jump...and for the most part you only need to hold onto your own domain name...and can switch to different underlying mechanisms/technology/providers/whatever...but the top-level identity is preserved as you cross to other instances, etc. Within the indieweb community - a community that supports efforts like ActivityPub, etc. - owning your own domain is usually the first step...because it represents the formal establishment of YOUR identity. An identity that you control, and where your friends/followers can always know and follow. I imagine in the future if more people adopt the practice of obtaining and sticking to using ONLY their domain name as an identifier, much of this will be easier and some it simply a moot point.
Having your own domain name represents YOUR identity/persona on the web - nay, overall internet in fact. The focus here is on the portion AFTER the @ symbol. Yes, unfortunately for now, owning your own domain - for the purposes of interacting with other instances and people via these federation-type of technologies - also involves the overhead of hosting your own mastodon, gnu social, pleroma, ActivityPub server, etc. But in the future, it could be that the underlying mechanisms could be made much easier and cheaper both to use and to switch/jump...and for the most part you only need to hold onto your own domain name...and can switch to different underlying mechanisms/technology/providers/whatever...but the top-level identity is preserved as you cross to other instances, etc. Within the indieweb community - a community that supports efforts like ActivityPub, etc. - owning your own domain is usually the first step...because it represents the formal establishment of YOUR identity. An identity that you control, and where your friends/followers can always know and follow. I imagine in the future if more people adopt the practice of obtaining and sticking to using ONLY their domain name as an identifier, much of this will be easier and some it simply a moot point.