How much closer is Bitcoin to being mainstream, and how do you gauge that? I noticed more ATMs in recent years, but other that haven't seen too many other signs.
One of the ways to gauge it is regulatory involvement and institutional investment options. These things tend to be purely reactive; they are not the "early adopters" of a technology. The fact that Bitcoin is getting so much attention from these groups (e.g. CFTC formally registering LedgerX for swap execution, or the new Bitcoin ETF to be listed on Canadian markets) says that it is definitely here to stay.
Commodities market insiders are also indicating that the SEC is getting closer to approving an ETF in the US as well. Once that happens, a big potential pool of investors could have access to BTC options.