Oh my goodness, really? I've been asking them to send emails when freelancers send proposals for years! I may pop back over to Upwork and send some proposals (haven't bothered in a month or so) just to see what difference this makes!
(YES, everybody, I CAN see how it might be overwhelming. But I also know the proportion of people who pop a listing in, and never interact with it again, is huge. Upwork has needed to do something about that, and about people who don't understand the UI and think the top few is all the proposals there are and if they don't like 'em, they walk away. Sure, they could fix the interface, but let's not wish for the stars...)