I've also found salary is not tied to interview difficulty. I've got really high job offers easily (3 hour on-site), and struggled to get the low paid ones beca

I've also found salary is not tied to interview difficulty. I've got really high job offers easily (3 hour on-site), and struggled to get the low paid ones because they're technical interview process is difficult/ boring (8 hour project work). Having said that, I think its more common to find higher salary paying jobs to be more selective/ difficult.