If the Gondolas were to replace the monorails place for place, I think there would be far too much to fix and change, and space is already tight... They couldn't go higher, so they'd have to go lower, and even then, would have to change the whole platform again.
Besides the issue of removing an icon (which we can debate), or whether they could fit, there are also the two big issues of capacity/throughput and all-weather operation.
1. The current monorail throughput of approximately 7000 passengers per hour still exceeds the Skyliner 4500 passengers per hour. I'm sure that Doppelmayr will be slowly inching that number up but I think people have also speculated how new cabin designs could increase the monorail capacity by 10-20%.
2. I *think* it's the case that the monorail is subject to fewer weather stoppages than a gondola system.
3. A smaller issue that I think we're allowed to discuss in this thread is that the monorails are air conditioned (inadequately though they may be, hopefully to be addressed in the next iteration).
4. Another smaller issue is whether the Skyliner would be more noisy for the rooms around it in the Contemporary.
5. It's not clear to me that it would be cheaper, given the number of stations and the number of turns. Unless they're going point-to-point across the lake...
6. Again, a smaller issue, but if they do a through station (like the Riviera), I'd be interested in the throughput of getting ECVs on and off vs. the monorail.
All in all, I don't think they'd choose to replace the Resort/Express monorail with the Skyliner. And the Epcot monorail is too long of a journey to make the Skyliner a preferable option, neither from the travel time perspective nor the air conditioning perspective.