Even Darrel Issa, probably the most aggressive representative that fought SOPA, besides Zoe Lofgren, said in an interview at Stanford I believe, that the politicians changed their minds about SOPA then not because of "the people" but because of the companies lobbying against it.
The US political system is in such a sad state of affairs when politicians have to hear from the corporate lobbyists first whether something is a good idea or not before listening to the people.
Who are "the people"? Probably 90% of the country never gave a shit about SOPA. Politicians weren't going to fundraising rallies in Iowa and having soccer moms and dads come up to them to talk their ears off about SOPA. From the perspective of a politician it's not "the people" versus "corporate lobbyists" it's "random public interest group" versus "representatives of big companies that create jobs."
And that's totally rational and democratic. A random public interest group may or may not represent an opinion that's broadly shared amongst the public and important enough "to the people" to get any votes. But everyone cares about jobs, and if a job-creating industry leader like Google says something is a good idea, then maybe it's one that'll create jobs and get you some votes.
The US political system is in such a sad state of affairs when politicians have to hear from the corporate lobbyists first whether something is a good idea or not before listening to the people.