Where I live there are no competitors for the one cable internet ISP (DSL is not available and satellite is n competitive). As such they have not need to worry about losing customers to _competitors_.

Based on this article, I suspect that ISPs like Comcast and Charter are not extending their backbone to handle growing internet traffic. It seems they are charging exorbitant fees to discourage increased usage instead (in this article, the subscriber canceled their Hulu account and lowered the resolution of video supplied by Netflix).

Having only one ISP locally is typically either caused by market size or local regulation. Comcast does offer a national backbone and sells transit, cdn and other similar services through a subsidiary called Comcast Technology Solutions. The backbone at a national level has definitely received upgrades and they are advertising multiple terabits of capacity. Of course upgrading the transit network does not help if your local link is saturated, which is a problem in some areas.

If there is truly demand for unmetered internet someone will step in and fill the void. Some ISPs also use total transfer as a way to discriminate between business internet and residential internet.

Those are both consumer ISPs, and thus not subject to the same market pressure as I described for Tier 1 ISPs (without naming them as such). Similarly, consumer divisions of Tier 1 ISPs are driven more by local market forces than anything else.

See also: https://en.m.wikipedia.org/wiki/Tier_2_network , https://en.m.wikipedia.org/wiki/Tier_1_network