Lol, what? There are a couple things deteriorating on FITH, but mainly on the outside building. The ride is about the same as ever. Some of the audio comes and goes with the seasons. Some years they blast the soundtrack, other years they have had cricket sounds or other music.
I feel like sometimes people forget that FITH is an old ride, and it hasn't changed that much. What people think is "falling apart" was normal back when it was new. The scenes have always been campy, the track has always been bumpy, and it's always going to be musty inside. The real problem with the ride is that they are maintaining the building itself. There's a huge hole near the start of the ride that has been growing for the past several seasons. I'm sure when the lights are on you can see all the water damage...
I'm by no means an expert, but these are some things that I noticed (perceived?) during my rides:
-Lack of ambient music (particularly the second scene)
-Transfer track area between 1st and 2nd scene seemed larger and is covered by a curtain that I do not remember being as large or as obvious as it is now.
-Water shooting over riders not working (this one is understandable given the condition of the building IMO)
-Lack of bridge-out sound effect
-replacement of original fire effects with smaller, weaker-looking (IMO) flames
Along with the already noted deterioration of the building.
Some of those might be subjective, or might lack the nuance of people able to go several times a year, but my point is this: I've been riding FITH on and off for 14 years. I perceive a decline, and I don't think I'm the only one feeling that way. Yes, the building's in terrible condition, but I wouldn't say that's the only place a decline is happening. I don't think this is simply "well, the ride's just old" anymore. Just my two cents.