I'd expect that given the state of the economy (with companies looking to shore up their finances and expecting a recession), the budget for conferences, paid for by businesses (whether attending, or sponsoring), are going to be drying up. Unfortunately, i think these conferences are the ones that bring in paid speakers.

The small, indie conferences would generally ask for volunteer speakers (at least, for small indie conferences that i have watched before), and so those could continue but not if the tickets are expensive, and also wouldn't bring in much revenue for the speakers generally. They are a labour of passion.