I think it's uncertainty (and fear of uncertainty) primarily. Then, there must be some popular bias about crypto in general (that you are required to be "geek", "tech expert", you have to be "rich" to enter, that it's "less serious" than traditional methods, that it's predominantly filled with "frauds" and "criminals" and is "not trustworthy"). Speaking of the latter... there are plenty of interested players who'd argument you why such prejudice/fears are completely rational & factual 100% just so you won't enter any competitor sphere.

Besides, you can see governments taking part in contributing to crypto's semi-legal indefinite status as well, by either delegitimizing it or seeking to control it.

And, as someone above correctly put it, crypto projects developed by big corporations (re: Libra) don't exactly add up some "trustworthy" image to crypto, being seen as marketing tool of the richest & further power establishing mean by them (while being simultaneously trashed by centralized govts seeking financial hegemony... how ironic).