The issue is that despite usability of Cadence being so much more confusing than Altium, you'll find that at some point when a design gets big/complex enough, Altium won't be able to handle it. This means that you've got companies who have to then move up from Altium to Cadence or Mentor to manage that complexity. If anyone is going to get into PCB design today (and it's an excellent field to get into, many people retiring and you can get a good job with just an AS degree) I would still recommend learning Altium before the other guys due to its popularity. I'm surprised to hear your thoughts about EMA though - I did a few webinars for them a couple of years ago and thought they had a great push to support customers. Perhaps I just didn't have the same perspective as the customers though.

The one thing that most surprises me about Altium is that they've yet to get into meaningful simulation territory (post-layout PCB extraction). This is the biggest feature holding them back from competing with the enterprise tools in my opinion. I was hoping for some continued collaboration with Simberian after the impedance calculator came out but have yet to see anything further.

I agree that Altium is the best for starting professionally. The very biggest and most complicated designs tend to move to Mentor because even Cadence eventually chokes. Simberean would be the one to develop a plugin, but they already have a standalone gui.