So, you liked Events. Before there was Events there was a different paradigm in iPhoto - Rolls. and that changed with iPhoto 08 and you'd have thought the world ended then too. There were loads of folks for whom Events were an impossible downgrade. But Rolls never came back. People adapted and learned. Events are gone.
I don't like the Photos interface but it's no more difficult to use that the Photos one. But that's me. Your feelings are different. But then, I was never that invested in Events and much more in Albums, Keywords and Smart Albums - so, using all the the tools, not just one.
As for the customers: most - and I do mean most by a very significant margin - Apple customers are mobile users on iPhones. Apple are thinking about those customers. The ones that wanted a way to manage and process images across the range of devices. Events make no sense on mobile. Moments do. So, no I don't think that Apple have forgotten their customers at all, but as in everything else they do, they provide a cheap or free app with 'good-enough-for-most-customers' features. If you want other features, buy a 3rd party app.
And really? Only 20k photos? I have 60k and guess what I did? I looked at Photos and said 'good for what it does, but not what I want' and went and bought the app that gets closest to my needs.