If these people has a choice -- as in, their ISP providing a (usable) IPv6 connectivity -- they wouldn't be complaining here in the first place.
In Germany, there are plenty. Only reason could be that you want native IPv4 as well. Then you might be limited in the more rural regions (that includes smaller cities).
I must stand corrected: some ISPs don't offer IPv6 for their commercial products.
I'm pretty sure some people would be very happy to pay for the tunnel service to get some sort of SLA, but there's just no such paid service being offered by HE.
I agree that would be nice. But on the other hand, we can't force them...
Also, you do know that you can build your own tunnel server? https://michael.stapelberg.de/Artikel/ipv6_tunnel
(it's in German, but you'll the important parts)
Well, I have no problem using the HE tunnel for commercial stuff (I didn't see where the usage policy forbids this), but I would feel obliged to tell my clients that there's no guarantee that this'll work all the time. What if HE decided to shut their tunnel servers down for good, with a few weeks notice (anyone remember gogo6)? What would he tell his customers? What if they have a 2 years contract, and suddenly he's not able to provide the services anymore? It's just a risk I wouldn't take, but it's up to everyone to do business as he likes. Again, no blame here, just arguments from my point of view. Live and let live.