Although big companies have been making inroads here against the little customer, which is indeed what has been encouraging big companies to add more and more of these ridiculous arbitration agreements. For example the article even mentions the AT&T Mobility v. Concepcion case which said that an arbitration agreement wording could be used to forbid going to arbitration as a class action.
The trouble is that there's a growing movement of anti-legal-system thinking out there, especially on the right wing. They see lawsuits as a problem, and trial lawyers as bad people (but a trial lawyer on your side is a good guy, trial lawyers for other people are the evil ones). Combine this with a pro-corporate attitude, and this means that these sorts of arbitration agreements may have a lot of support in congress.