(Unless I'm misunderstanding, you can charge for GPL software, you just cannot charge for the source once they've got a binary. You also can use your own fork of GPL on your hardware without releasing any source.)
See https://www.gnu.org/licenses/gpl-faq.html#DoesTheGPLAllowMon...
I believe this is no longer true (at least in general) as of GPL v3. In fact this "Tivoization" is one of the very things the GPLv3 was intended to combat.
Software-as-a-Service is another thing they were aiming at... I don't know offhand if it made it into GPLv3 or not.