If compensation was offered for an interview process, then it's worth the time spent going through the interviews.

Otherwise, it feels like a gamble of a huge time sink that could have gone towards something actually beneficial/profitable.

Having had too much of my time and energy drained in the past with the run around, I said fuck it the last time when facing the option to interview or go my own way, started my own thing and haven't looked back since.

Even when you do get an offer, it's a gamble on whether or not you're dealing with toxic management or not. Which only reinforces the idea of compensation for interviewing in case someone needs to jump that ship and start interviewing again.