You are always welcome to use the opportunity and start a competing service in a fraction of the cost. Mastodon is indeed inefficient but you also pay a lot for peace of mind.
More to the point: the masto.host guy has been there working on making starting an instance accessible from early on. People don't seem to mind paying a little premium to support someone who's done a lot of work to jumpstart the fediverse. Starting a competing service might be easy from a technical aspect, but reputation counts for a lot here.