A bit of a different perspective: as a CS undergrad in Silicon Valley, internships routinely pay upwards of $20k for a summer, complete with relocation -- simultaneously defraying costs of tuition and providing real work experience.

Far from being a mechanism to filter for the upper class, the interns I've worked with came from a diverse range of backgrounds, local, foreign, and all across the States. The tech industry might like to overstate the amount of meritocracy in its system, but at least in this regard internships seem to do well at providing more equal opportunities.