I am experiencing the same problem. I am using one of Germany's largest Internet provider (T-Online) with a recent DSL/router combo that is handed out by them to their customers (Speedport W 303V, got is 6 months ago, updated to the newest firmware). So I think that probably a larger number of people than you think are affected by this bug (at least in Germany). I was able to bring my system into a usable state with the workaround of disabling IPv6 in the kernel by editing grub config file. But non-technical people, who cannot do things like that, will have a very bad experience and probably stop using Ubuntu, because the network is unusably slow for them. Please take this bug serious. I would say it is critical.
I am experiencing the same problem. I am using one of Germany's largest Internet provider (T-Online) with a recent DSL/router combo that is handed out by them to their customers (Speedport W 303V, got is 6 months ago, updated to the newest firmware). So I think that probably a larger number of people than you think are affected by this bug (at least in Germany). I was able to bring my system into a usable state with the workaround of disabling IPv6 in the kernel by editing grub config file. But non-technical people, who cannot do things like that, will have a very bad experience and probably stop using Ubuntu, because the network is unusably slow for them. Please take this bug serious. I would say it is critical.