IPv4 address with more address bits would have worse, because it would have the same incompatibility problem as IPv6, without its benefits.
Actually, IPv6 is good design. Adoption is slow because most people and companies always prefer a cheap short term inferior solution compared to the good long term one.
Now, IPv6 is 25% of traffic. It will continue to grow, and at a point the network effect will be on IPv6 side. Not long after that, IPv4 will only be a niche for a few legacy systems.
Nitpick: it's 25% (or 29% peak) of clients. As for traffic... dual-stacked eye-ball clients see about 50-70% of their traffic go over v6 on average.
(What about percentage of overall traffic on the internet? That's much harder to measure, but you'd expect it to be something like the product of 25% and 50-70%. But that particular stat isn't actually very interesting; percentage of clients and percentage of servers/traffic are a lot more useful.)
Actually, IPv6 is good design. Adoption is slow because most people and companies always prefer a cheap short term inferior solution compared to the good long term one.
Now, IPv6 is 25% of traffic. It will continue to grow, and at a point the network effect will be on IPv6 side. Not long after that, IPv4 will only be a niche for a few legacy systems.