There is a big part you are missing, and that is service life and repair costs of steel coasters compared to wooden coasters, and that is why we see things like Vortex, Firehawk, and King Cobra disappear, and eventually The Bat will leave...that plays a much bigger role than "community" opinion or a "debate of do we fix an old coaster or just build a new one" on when a steel coaster is removed.
And don't mistake a paint job as it means it will be around a lot longer. King Cobra was repainted and was gone a year or two afterwards. Slingshot was painted and then removed without re-opening....
A wood coaster can last longer because it is easy for the parks to buy lumber in bulk and the type of laborer needed and access to the piece that needs replaced is easier than for a steel coaster.
Our wooden coasters are walked daily and if you visit enough, there are times you can see a piece of wood has been replaced mid-season as a result of these daily inspections. And then sometimes we get off-season sections replaced as we have seen recently. Due to the design of the wooden coasters (walking paths the entire length) and the type of laborer needed for wood (compared to a welder), it is cheaper to maintain wooden coaster than a steel coaster.
While steel is stronger than wood, it is subject to higher loads, fatigue and as such has a defined service life. Sometimes the service life is shorter than expected, and sometimes it is longer. So many factors come into play. Maybe it got bad steel; or the stress loads were higher than anticipated; or the temperature of the location of the ride impacted the steel more while it was being operated. Steel can only handle so many cycles before it starts to fatigue and it typically deforms and weakens at the welds. Steel coasters are subject to annual non-destructive testing inspections for the integrity of the welds. Other testing such as holiday testing, ultrasound, and several other methods are used to detect imperfections that are not visible to the naked eye. At some point these inspections provide how much longer the ride is able to operate until wide-scale fatigue failure occurs. Sometimes is matches up with the intended design life, and sometimes it doesn't.
Part of the maintenance of steel coasters is repairing any welds that are beginning to fatigue. This is extremely expensive. The ride manufacturers require certain methods, type of welds, materials, etc. to be used on their rides. Plus, unlike wooden coasters with a walking track the entire length, steel coasters usually only have that on the lift hill, MCBR, and final brake run. So now you need cranes or other equipment to hoist the laborer and material in place. With a wood coaster, you can carry a couple of pieces of lumber with you to the location. The specialty labor required for a steel coaster weld repair, along with the parts cost is orders of magnitude greater than for a wooden coaster.
You may be asking well why don't parks re-track and replace components yearly on their steel coasters like they do for wooden coasters? Again, the answer is cost. Depending on the nature of the repair, it could cost more to repair than a new coaster. Same thing with automobiles - sometimes the cost to repair a vehicle after a crash is more expensive than just buying a new car. Or restaurants. Many times it is cheaper to demolish and rebuild on site than it would be to remodel and get it up to current code.
The initial build and fabrication of the steel coaster is always cheaper in the factory and onsite in an open field than 30-something years later. Access is more difficult, more levels of approvals are needed. More specialized laborers are needed. The cost of the materials are more expensive, etc.
Further, by the time the ride has reached its original design life, many of these rides will have lost enough ridership as they have aged that the ride's popularity would not justify replacing all the steel components needing replacement, especially if it would be cheaper to simply build a new coaster. As it relates to The Bat, it does have going for it that the segments are bolted instead of welded like older Arrow coasters, so if there were sections that came back that were more fatigued than others, it could be possible. But there is still a lot of welding on The Bat.
Does that mean that no steel coaster is ever rehabbed and track replaced - no - it has happened and will continue to happen on a case-by-case basis.
But for something like The Bat, I could only see KI keep it around beyond its service life with rehab if ACE provided funds to do so to "preserve" an Arrow Suspended Coaster and I just don't see that happening...