Why can't we just connect a really long cable from the moon back to earth and wrap it in insulation??

There’s a 50k km difference between the shortest and longest answer to “how far is the moon?”, depending on orbit and phase. The distance can change by about 75m per second.

I don’t know of a reel that can spool up a cable at 270 km/h.

Our current longest power cable is 5376 m long. So we’re only 406k km short of bridging the gap (our longest is only 0.0013% the length required).