Frequency is irrelevant without context, you're ignoring the context because you already think you know the reason for the increased frequency - Republicans are assholes - which is mind-boggling.

What is actually happening? Simple, easy, and surprisingly more reasonable than GOP=evil. In the past bills virtually never hit the floor until the outcome was essentially known. Filibusters took place rarely because the Sen Majority leader wouldn't often put a bill on the floor he thought was going to get filibustered. That is all. When it happened it was because someone found an implication of the bill that really worried them and a lot of others, or because the president was ramming it on them, which rarely happened because the senate hates when POTUS pushes them.

So the reason for all the recent filibusters is Harry Reid himself. Now he's not dumb, but he seems content to shrug at his own hardliners or POTUS and say "Sure, we'll drop it on the floor." I don't know if they've just pushed at him so much this is his way of trying to shut them up and school them simultaneously or if he just gets kicks from filibusters or what. But that is the cause. The GOP keeps filibustering everything mostly because of what is being presented to them. And, of course, even things that might have avoided filibuster in the past get filibustered because the collegial atmosphere has been eroded. There's no courtesy and future favor preventing someone who doesn't like a bill from filibustering now. If you want to put that all on the GOP, then go ahead, it's stupid, but whatever.

When the Dems seized both houses in 2006 they were coming off from several years of anger and elected a lot of angry people, the GOP did much the same in 2010. In a way I approve, I don't like the senate and until recently every senator thought he was a god. Their collegial attitude mostly came at the voter's expense, but it did keep things polite. We've had wads of senators who'd been squatting smugly on their fiefdoms for decades resigning and retiring and snapping off comments about how things have changed for the worse but what they mostly really mean is that people aren't bowing and scraping and licking their boots before begging favors like they used to. They are acting more partisan, which may not be the best thing in the world but it is better then the flavor of non-partisan they used to have which had more to do with ego-fluffing and reach-arounds than sitting down to discuss things on their merits and seeking merit-based compromises. I don't want them to sit down and achieve a compromise where each one of them gets something, I want them to reach a compromise that produces a streamlined concept that leaves the majority of people convinced it is a good compromise solution, not a good compromise of solutions.