It's also not always about adding more rides, but updating rides that are no longer relevant/popular. Epcot has major people eaters but they are no longer popular like before: Journey Into Imagination, Nemo, Living with the Land, Gran Fiesta Tour all have great capacity, but they aren't popular so that capacity goes to waste. Everyone wants to ride Test Track and Frozen but those have ridicously low ride capacity.
The last several times I was there, Gran Fiesta Tour was not able to contain its line within the pre-existing queue and I can't recall the last time there was no wait for Living With the Land.
Mind you, I can't recall Gran Fiesta ever having a 45 minute + wait but they also don't have the space in that pavilion to contain such a line without reducing retail space (which is a sin above all others these days) and Living With the Land is usually 45 minutes or less but I've not seen either with unused capacity in
many years.
Nemo and (especially) Journey, absolutely - I'd say the whole Imagination pavilion is a waste. The image works was awesome, the current post show was crappy when it opened and it's now, just pathetic.
Not trying to argue that any older attraction couldn't benefit from regular and routine updates but honestly, the biggest problem with two out of those four you've mentioned is that they
were actually significantly overhauled and they ended up with something that was less than what they'd started with.
I've no doubt that the original Imagination ride with no changes would be horribly out-of-date today and the hydrolators were past their prime when they pulled that plug but the problem with these current replacements is that they weren't that good to begin with and have thusly, aged way more quickly than their predecessors.
So there is a balance to be struck between building something quality that will be (please forgive me for using this term) timeless and knowing when it's time to update to keep something that isn't timeless, relevant.
Personally, I've seen nothing from current management over that last decade+ that suggests they have a handle on or a desire to be better at either as long as they keep revenue during their tenure up.