It's not as we are carving out v4 /8's (1/256 of space) for early adopters. Or even /16's. More like the equivalent space of a host address. That's hardly too much. In fact, it's way too little for those ISPs which have home customers like DSL, and it's going to be a a pain because they either must get a new prefix or give their customers a /64 instead of /48.
I think that if an ISP can show that they have more than 65536 home DSL customers, they will not have a problem getting a /31 or larger as needed. However, I think that today, the bulk of DSL ISPs doe not have that many customers and aren't likely to in the near future.
Uhh, I'd say there are a thousand or two such ISPs in the world. That's not insignificant. It isn't useful to be stingy when allocating prefixes to ISPs which _might_ end up needing more than a /32 for their customer /48 assignments.
1. I think you seriously overestimate the number of DSL subscribers. In order for there to be 1,000 such ISPs, by definition, there would need to be at least 65,536,999 DSL customers of those 1,000 ISPs, and they would have to be very evenly divided amongst said providers. 2. Such providers will have no difficulty whatsoever getting a /30 today (which covers them for 256k customers).
And if such ISPs decide that rather than going through the process of justifying more space, they end up giving the customers /64's instead.. well, the result might not be pretty.
To paraphrase Randy again: "I encourage my competitors to try this." Owen