Mainstream public, the other TLDs are not popular at all. Especially true when you don't include the www. as part of the url.

Internet audience sure, not as big of a deal (but still a deal).

I'm sure as each year goes by and older people die out/adapt .com won't be that big of deal

The issue mostly comes down to whether or not search engines (and other web entities) should treat TLD's as pure namespacing items or actual indicators of geography (the classic case being ".tv" - were you trying to indicate that your site was related to Tuvalu, or that it was about a sitcom?)

It's something that is still in flux, I believe it was within the last 12 months that Google officially switched over to treating ".io" as a generic TLD instead of country specific.

For reference, they have a listing here:

https://support.google.com/webmasters/answer/1347922?hl=en