If DANE were to roll out to browsers, I think plenty of people would rather use it than centralizing on Let's Encrypt.

DNSSEC isn't easy, but either is certbot. DNSSEC also isn't that hard if you're not self-hosting your DNS servers (and even then it's easy if you pick a modern DNS server).

Most domains seem to use their registrars free DNS servers. For those domains, DNSSEC is often just a checkbox. I just activated DNSSEC on three domains by hitting that checkbox. A certbot-style tool can use the same API many existing certbot plugins already provide access to for setting up DANE.

However, until browsers actually implement DANE, it's pretty useless. I know some people use it for mail servers (for some reason, don't see why they can't use Let's Encrypt for that) but even there it's optional.