Not for the iMac they haven't. In fact they are still on the 27" iMacs sold by Apple right now, but I don't want a crappy Intel machine.
Anyway, I'm all for usb-c or lightning or thunderbolt, or even some new faster standard we don't have yet being developed. The issue is there are lots of devices that don't need fast transfer speeds and making them use a different port is just expensive and a headache for the users.
And then there are new products like the $2,000 drone I just bought that doesn't have a USB-C port. USB-C is not a universal standard and people still need to plug in a lot of USB legacy devices.
Maybe dongles are just a minor annoyance, but I've always admired the clean look of the imacs. And I'm used to tons of USB ports on my Windows machines. Anyway, I'm a techie who always loves having way more ports than I need so I say give me it all, HDMI, Displayport, USB, USBc, ethernet, thunderbolt, whatever. Who knows when I'll need to use it.