I may be missing the ball completely on the Universal buildup, but I don't think they're within stricking distance of Disney in the 80's. Not by a mile.
I'd say the Resort Hotel Buildup at Universal has been greatly exaggerated and blown out of proportion.
Think about this for a second, since 2010 Universal has added 1800 rooms. If you were reading some of these forums you'd think Disney had been sitting around doing nothing. Instead, Disney has launched Art of Animation (more then 1600 rooms just there), DVC Grand Floridian, and DVC Polynesian. This was just after a extensive build-up that launched 695 new DVC properties in 2009.
http://articles.orlandosentinel.com/2009-01-12/business/hotelsrail12_1_share-resort-disney
This was all during a recession and recovery in which tourism dollars were scarce.
These room additions dwarf (hah) Universal expansion. Even with the Sapphire Project underway over at their property, Disney would still have competitive unit expansion (with many of those rooms bought for the next 5 decades). Also now and fall of 2016 is long enough away that Disney could easily begin construction on new properties.
Disney during the 80's was all about boundary pushing. Whereas Disney didn't know if a third gate would really work, they did it anyway. They didn't know if Resort Buildup would really work, but they did it anyway. They didn't know if Pleasure Island would work, but they did it anyway. I think we occasionally forget just how revolutionary Walt Disney World is. Thanks to WDW Universal is following a model created by Disney. Disney didn't have that model during the 80's.
Update: 100% Volcano Bay is big news. It seems to be getting under reported everywhere.