ISPs won't bother with IPv6 until they've either run out of IPv4 space or the internet starts to use IPv6's advantages.

Discussions about IPv6 quickly end with "we have enough v4 space and there are no services that require v6 anyway". As long as the extra cruft for v4 support remains free or even supported, large ISPs won't care. We're at the point where people need to deal with things like peer to peer connectivity with two sides behind CGNAT which require dedicated effort to even work.

I know it sucks if none of the ISPs in your area support IPv6 and you're left with suboptimal solutions like tunnels from HE, but I think it's only reasonable all this extra cost or effort becomes visible at some point. Half the world is on v6, legacy v4-only connections are becoming the minority now.