Even if that scenario did happen (I agree I don't think most of the major providers would survive on a commodity utility model). Most of the advances in AI are driven by huge amounts of funding for research. If everyone goes to open source models/utility based pricing etc then it'll be cheaper but the current rate of improvements are being overwhelmingly driven by the frontier labs (for better or worse) and they're being driven by vast amounts of VC funding predicated on making vast amounts of money.

I'm very dubious we can have our cake and eat it of constant magnitude order improvements and also commodified utility pricing.