Everything looks legit, and the switch seems to work reliably when I mess with it, and after I let it cool off for about 10 minutes in the "off" position on the knob last night it ran like a scalded dog for the next 2 loads. Seriously, when it's working it runs better than it ever has. I'm thinking it just can't be the motor or transmission because that would give me problems all the time, right?
Since I haven't been able to catch it in the act, I can't confirm if it comes on and just "hums" instead of entering the spin cycle or if it simply does nothing like a lid switch problem would indicate. I'm with you in your thoughts about wiring or the lid switch. Do lid switches ever cause intermittently failures or low voltage conditions?
With the cabinet off and the lid switch jumped out I would put the washer in the spin cycle and then wiggle the motor wire harness and plug to see if I could get it to quit spinning.