Yep. I think the assumption was that the old parade warehouse would be demolished to make room. I can't remember when they built the new warehouse, but I think it was around 2008 when the Pixar Play Parade started.
The "new" parade barn (located next to the Screamin' station) was built in early 2001, in preparation for the Electrical Parade. Considering how hastily it was added in a budget-conscious era, it actually looks pretty decent (assuming you're okay with backstage infrastructure being visible inside the park, which is a whole different can of worms). As far as I know, this has been the "main" parade barn since Eureka!'s retirement, but I don't know what the other facility is used for now
Considering the World of Color viewing area is directly on the parade route, it's safe to assume that DCA won't ever run a nighttime parade again. If they're only running one parade at a time, even with seasonal entertainment and street shows, they should be able to function just fine with the single parade barn; DL has been running with just one for years and they have 2 daily parades and plenty of seasonal additions
EDIT: If they need more parade space in the future, they could always use part of the service road that runs behind the park. It hasn't been used in any meaningful capacity since the Timon lot closed to guests, and parts of it are already used for equipment storage. If that road is in play, there's a ton of space behind Screamin' to reconfigure the backstage layout
DCA has had three parades in it's existence including the Electrical Parade it stole from DL. Isn't it time for something new?
DCA has actually had 4 parades in its 15-year life: Disney's Eureka! A California Parade (yes, that's the real name), Disney's Electrical Parade, Block Party Bash, and Pixar Play Parade, along with an even more pathetic version of the Halloween party cavalcade, which I won't even count.
That said, I agree that it's time for a new parade. PPP has been running (on and off) for 8 years now, which seems like long enough