It's not ridiculous. First, it requires the NSA to actually do what you propose, as opposed to just reading broadly all traffic going through. That is a big difference because it gives the possibility of Wikipedia fighting back. Jimmy Wales has suggested that if he's ever given a FISA gag order, he might disobey it: https://twitter.com/jimmy_wales/status/362596285469044737)
He might disobey a personal gag order, but I can assure you that as long as PRISM exists, U.S. companies will comply if targeted.
There are also plenty of other attack vectors for the NSA even with HTTPS; obtaining the private keys of the common certification authorities is perhaps the most straightforward.
