With ISP's, in most cases only a few are available - and in some cases, only one per type of available service (cable, DSL, Dial-up, Sat.).
Sure, in an urban area there may be more options, but if you live in a rural area, your options are very limited.
I know that for a lengthy period the only available options at my location were dial-up or satellite - sat was a bit costly, and we were holding for the cable install (at the time, it was expected to take less time than it did).
No DSL available, as I live too far from the nearest hub.
No Cable, as the cable lines were never installed at the house I live in.
After much maneuvering (and ~1-2 years), cable lines were extended to our residence - as a direct result of new construction next door.
But still, the only cable ISP I'm aware of for our area is Comcast, so if they were to put restrictions on the traffic, well...
And while basic browsing/email is possible via dial-up, online gaming (especially FPS and similar) is nearly impossible.