I find it deeply troubling that there are still plenty of conferences that charge speakers for speaking (!). Yes, it is indeed that fucked up! I understand how some prestigious conferences can get away with only giving speakers free conference passes and still attract good talent. Still, the best conferences out there don't stop there: they also cover your travel expenses and sometimes give a small honorarium, which is great. It works wonders to increase the quality of presentations and overall conference experience!
Now, vendor speaking ops are a bit of a different story; a vendor might sponsor a conference and get a speaking slot, clearly marked as such.
However, think what kind of speaker a "pay for play" conference will attract? This automatically means that all people attending a pay-to-speak conference are scammed out of their hard-earned dollars. So, it boggles my mind why would someone ever attend a conference where the only speaker selection criteria is: "Got 3 grand? You ARE an expert here!"
Before signing up for that next security conference, think: is it a pay-to-play scam?