No one manufacturer dares ship a product with the wireless at anything other than the legal maximum strength. Doing so would put them at a severe competitive disadvantage as clueless users return their product and exchange it for the competitor's one that has longer range.
So while a great idea, it simply won't happen.
What we really need is a combination of a few things.
1) more available wireless channels
2) device manufacturers who actually support all the existing channels.
3) router manufacturers making it harder to use channels that overlap with other channels
Right now there are many brand new devices which don't support the 5GHz band, making people resort to only using the 2.4 GHz band. 2.4 GHz only has 3 channels which don't overlap each other (1, 6, 11) (talking north america here) but people frequently place their routers on other channels. When someone puts a router on channel 3, it interferes with both channel 1, and channel 6, and worse than if they had chosen either of those channels specifically (as routers are designed to work with co-channel interference)
Then you get in to the 5GHz band and find out that many manufacturers don't support the DFS channels (anything below 144) which further limits the options.
Then you put your router in an apartment complex with 500 other routers and wonder why you can't get 1 Gbps through it...