Filthy, broken and disgusting have a lot to do with maintainability.

Ask the common route dude whether he's going to strip five layers of plastics held on with screws that, if you slip, drop into places that you must then dismantle damn near the entire playfield to just to change a LAMP and make sure you're beyond thrown object range.

Stapled GI sockets? That's 1970s stuff, and when it was 1970s playfield design where you could unscrew a plastic and get to the bulb from the top, no big deal. Now try it on Apollo 13 with the GI back near the ramps where there are two or three layered plastics AND metal intertwined (e.g. ramps, the 8-ball trough, etc) that have to be dismantled and removed because that stapled socket precludes access from the bottom; that'll be 30+ minutes to change ONE blown lamp. Think it's going to get changed by the route dude on his regular visit? Uh.... no. How many machines have rubber parts (wear items, natch) mounted in such a way that you CANNOT change them without stripping off multiple layers of plastics -- and sometimes mechanicals -- first?

It only gets worse -- a lot worse -- when it's not a cosmetic, it's a functional matter. Pop bumpers on the same machine? Remove all the ramp plastics AND habitrail ramp off the bottom to get to those, plus the couple of layers of playfield plastics above them. Oh, and don't drop any of the screws in the process. THEN you can get the pop cap off, and start disassembly. How often is that going to happen so you can clean the dish and set the gap on the switch correctly? That's what I thought. Coil access on the rocket? Have fun.

GM did the same sort of thing in the 1980s with cars that required jacking the engine out of the vehicle to get to the spark plugs, with the same result.

It's not impossible to design wire looms that allow for easy removal of things like subways, making sure there is clearance to R&R mechanisms without having to dismantle six layers of "stuff" first and, if you must layer playfield plastics with fasteners use captive fasteners that can't fall into the machine and force a more-complete disassembly to retrieve them -- along with a clear and logical order to get them apart and back together again *quickly.* In fact 3d modeling (which is now a commodity product; hell, I own it on my desktop PC!) now makes such things fairly easy to do and assembly/disassembly clearances can be verified before a single part is constructed.

You want route operators (or anyone else) to pay $9 large for highly-complex devices and then ask people to stuff dollars instead of quarters into them they have got to work, they have got to be fun, ball times have to be reasonable and while #3 is to a large degree a design issue in order for #1 and #2 to happen they *have to be easily and rapidly maintainable by the average route dude who is only halfway competent.*

The lack of attention to any of that is what killed Pinball and the manufacturers have NOT learned a thing in the intervening years. I still marvel at under-playfield components on modern machines that cannot be accessed without major disassembly and pain; heck, on some machines it's tough to get the requisite allen key in the flipper pawl nut so you can tighten down the clamp bolt due to interference with under-playfield wiring and mechanicals! How hard would it have been for Williams (or anyone else for that matter) to use a hex bolt and a captive washer that locked it so you only had to put a wrench on the nut on the other side? 30 seconds worth of trouble to make that part for the assembly but nobody has despite how many years of this sort of thing?