...because traps are so underpowered.
Anyway, it seems reasonable to me that a fortress with heavy reliance on mechanical contraptions should need a bit of support staff. I think it would be neat to have a bunch of mechanics scurrying about keeping things ship-shape. Dwarfy. That said, I agree that mechanical failure should be essentially preventable, and that the player should feel "oops" rather than "what the q***!" when it happens. Degree of shoddiness should be displayed.
Other considerations aside, I also agree that heavy and continuous use should be more demanding. Failures should be a Poisson process, i.e. as time passes without maintenance, more and more things start to fail, but there's no upper bound on the amount of time to failure. (Ancient traps/mechanisms discovered in working condition = fun)
The problem with that is that your basic traps are going to take up about 30-50 mechanisms.
A Four-function calculator or a dwarven Turing machine take tens if not hundreds of thousands of mechanisms.
That's several orders of magnitude more mechanisms, which in turn means that even if you only needed one dwarf just maintaining 40 mechanisms, then to maintain 40,000 mechanisms, you need 1,000 dwarves on nothing but maintainance duty. Plus, you know, all the support staff to feed and clothe and protect them, plus the dwarves to build the project.
Plus what happens when all your doors get jammed stuck, you don't see the message, and all of a sudden, half your fort starves to death because they were locked out of the food warehouse, or the drain to the waterfall got clogged, and the fortress flooded.
I only see this as a way to randomly spring punishment on players for not weeding out the one important message in all the message spam, and make the truly great megaprojects impossible.
There's some talk about making this into an init option.
And have broken mechanism automatically generate a "fix me" option.
Or have mechanism always goes through the following 3 state (check on a seasonal basis?).
1. Working - Mechanism work as intended. May advance to 2A or 2B.
2A. Dirty - Mechanism still working but may jam or break in a season or more (will work for at least a season). Will trigger a maintainance request for mechanics to come and clean/maintain it. Can only advnce to 3A when it comes up.
2B. Worn - Mechanism still working but may jam or break in a season or more (will work for at least a season). Will trigger a maintainance request for mechanics to come and replace it (takes a new mechanism).
3A. Jammed - Mechanism no longer work require mechanic to go and unjam it. Can advance to either 3A or 3B.
3B. Broken - Mechanism no longer work, the structure is still intact, but now requier mechanics hauling a new mechanism to replace it (structures depending on mechanism such as gears will not deconstruct, but simply have the mechanism component labelled as broken).
The path (A or B) taken depends on the quality, material, and the time in use of said mechanism.
Higher quality mechanism will advance from 1 ~ 3 much slower and will more likely take the A route versus the B route. No quality mechanism may need replacement almost every year. Masterwork should probably take about 2 years to go from working to worn and several years to need replacement. Artifact mechanism would never break, but will still need cleaning (only take A path).
This mean that early on, you must rely on less mechanism (or hand-pick for masterwork to reduce maintenance) else
Mechanism material should also have an effect, for example, steel mechanism should triple the time needed between maintainence/replacement.