I find these results questionable at best... I know that Data Architects make a very large amount, and if so then they make much higher than some DBA's that I know. Also, if you look at the payscale and yearly growth rate, it could take 2-3 years for a MySQL DBA to move from 67,800 to 72,500.
Which oracle license? They come in 5 varieties. The highest one was about $35kUSD, per processor. But no one pays the full price. Most places receive heavy discounts off the top based on quantity purchased, so suddenly your $35-40k license is now $15-20k. In my last company, we found we didn't need most of what enterprise edition offered in a lot of the systems so they downgraded to se1, I think. The biggest issue I see is that a lot of small businesses get suckered into buying EE licenses when all they need is SE1. Sure it has a 4 cpu max, but I haven't seen any small businesses buying anything bigger than 4 cpu's anyways.
Edit: Also, here's the biggest difference. With Oracle (like MySQL), you can download and install an unlicensed copy on your systems, for proof of concept or the like, I personally wouldn't see the need to do this (especially w/ Oracle XE). They just won't support you (thus making this unfit for any development/qa or production database).
No, I wouldn't say that $67,800 to $72,500 is a big leap, it's merely cost of living increases, because you know, IT people don't get paid much more for better performance.