If more bigtime artists take the Jimmy Buffett route and go independent, the record companies as we know them today will simply not be able to survive.
This is, as far as I can see, a fact.
It therefore makes sense that they now are fearing the influence of the online music stores; it appears as if anyone whose sales are worth the megabytes can get on iTunes -- from any cooperating label, including of course independent labels.
If a successful and profitable musician's contract comes up and he or she is considering going independent, the record company has two options:
a) let them go, killing the goose that laid the golden egg
b) Offering a raise, which may or may not be persuasive, and costs money if it is.
The reason that the RIAA members fear online music distribution is very simple:
It makes it possible for independent music to be highly successful.