I don't think the problem is as much that end-users don't care enough to want alternatives, but that it's near impossible for an alternative to exist. During the dot-com era when PayPal came about, there were many other 3rd party processors doing the same thing, and they went out of business primarily because they were losing more to fraud than they were making on fees. PayPal was losing tens of millions of dollars a month at one point, but they managed to create good enough screening systems and policies in place to stay in business.

These days even if another company were to manage the fraud as well (which will almost automatically make them as bad as PayPal with freezing funds and accounts... you know real merchant accounts underwritten by banks do this too), but the regulatory climate around finance is so different that they'd be unlikely to get off the ground. Visa/MC/Amex/Discover would never agree to allow such large scale factoring (accepting payments on behalf of another business, forbidden in every standard merchant account agreement) again.