There's a lot of "going-through-the-motions" recruiting going on. That is to say that they'll put you through an interviewing process, but you'll never get in, no matter how well you do. There are a number of reasons this goes on. One of them is an organization's ability to pat themselves on the back by "hiring only the best" and letting current employees do the interviewing, a self-fulfilling prophecy. It's like a game show where the host has all the answers and if you miss a single one, they have some lovely parting gifts for you.

These organizations tend to suck up a lot of the oxygen in the room. So for perhaps 20 of those 30 of your interviews, there's plenty of good talent that they turn their nose up at. Speaking from experience, the harsher the interview, the more likely it is to be the case that you never had a chance.

If you're going through spammy recruiters, consider not. There's a factor of cognitive dissonance going on where prospective employers want to hire you, but can't get past the principle of paying the recruiter's spiff (if you're seeking $180k on contract, this would've been ok, but not by the time they add the recruiter fee, they decide you're not worth $205k). The employer will waste everybody's time in the process. This looks good (they think) to the investors.

Push instead of pull to get your next job. LinkedIn, AngelList, a number of other sites.. when it's a good fit, the interview will be suspiciously easy.