Might depend a lot on the conditions in the spots where you a riding, and many other factors. I would put it the other way around instead - why are wings so good?
I am using 2.5, 3.0 and 3.6 m2 wings the most, 2 boards and 2 different front wings, and often there are no kites in the water at all, despite this being a crazy popular kite surfing spot. If there are kites they are usually on sizes 5 - 8 m2 (or 6-12 m2 for the bigger guys) depending on a day. I am not counting the ones who don't use the energy of the waves that much (twin tip riders would go crazy with their kite sizes). So, merely ca 1 m2 difference between the smallest and largest wing, compared to a solid 3-4 m2 difference easy for the ones who kite. That said, kite foiling is not that popular around here, a few are learning, but are using super big kites, a few can do it but have lost interest.
If you find the usable range of your wings to be too small, perhaps your entire setup and the technique as well can be optimised and fine tuned a bit?