It is stock and works fine. Better there than someone putting their drink behind the window and emptying on the controls. Not a terrible amount of room on the console otherwise.
Everything is waterproof - and you could quickly rinse it off, if needed. But I looked at a picture of a 180 console and I see what you're talking about.
So... couple thoughts, in no particular order...
-- First, I hear 'ya on trying to stay sane! A little boat project would be the perfect remedy!
-- Don't worry about drilling holes (small or big). You won't have any issues with that due to the age - nothing will be "brittle". Trust me, I've done A LOT more to boats much older than yours... and many, many times! You might find a couple spots (they don't have to be right next to each other) where you can drop in flush-mount cupholders... maybe all the way on the top of the console... maybe on that flat, horizontal section above the steering wheel - left side, center or right (I can't tell if there's enough room to physically mount a drop-in cupholder from the pics, though).
-- There are also "fold-up" cupholders you can get. They're a bit on the flimsy side, but when not being used they fold virtually flat to the surface they're mounted on. There's even cupholders that have large suctions cup mounts.
-- If you decide to do something similar to what you currently have again, definitely make it out of starboard (HDPE). You can also buy pre-made ones like that.
-- Be sure to check out that Teak Isle mfg site - they have a vast catalog of HDPE stuff. Also look at a place like TH Marine or just google for "starboard cupholder"
-- If you want to make it yourself, it can be made stronger and better - there's couple ways you can do that.