Blink has diverged enough from WebKit that they are separate engines now. KHTML has been sadly laid to rest.
It’s a miserable state of affairs that we are effectively down to just 3 browser engines now, Blink, WebKit and Gecko. But with the ever increasing scope and complexity of web standards I don’t see that changing, unless someone throws a lot of extra support at the Servo project.
Yes, it’s a sad state of affairs that Apple’s restrictions on iOS and iPadOS browsers are the only thing stopping an effective Google monopoly over web browsers. Ideally Firefox would still keep things in balance, but Mozilla doesn’t seem to know what it’s doing these days in terms of building market share - and I say that as a long time Firefox user.
I still remember the IE 6 era, and I hope we never see a single browser dominate the web again. To those wishing Apple would be forced to open up, be careful what you wish for.