At all the good universities, the computer science department is also part of the electrical engineering department. Thus you have valuable research going on which crosses between hardware, software, information theory, physics, etc.
The people running these departments know that along the way, a few somewhat promising computer scientists will get sucked into reading philosophy books as a hobby, and lose their way in the world. These people become PL researchers (in the sense you're using the phrase) . The school earmarks minimal funds and provides minimal infrastructure, like a USENET group or a mailing list for these types (no pun intended). They know by doing this they will successfully keep them from messing up useful research (best case) or living on the streets (worst case).