the tape may last 30 years. but do you really expect the tape drive to last that long, or, to even be able to get a tape drive that works in the future.

That was my big problem with the economics of tape. the drives are expensive and don't really last that long. At some scale factor tape makes sense, but it is larger than you would naively think.

As there is no good solution for personal scale long term archive type storage, I have sort of given up on it. Actual long term archives take the form of human readable printed documents. However this is very low density. so only the most important stuff. long term bulk storage is live, hard drives based arrays and backups, requiring an active maintainer it will die when I do, but no great loss, it is mostly junk anyhow.