"I've replaced those for a less than
$200 DIY. Two bolts on the mount, two on the flange, and three wires.
Half hour of labor"

*grin*..would that it had been that easy! This was a big, 50 year old motor/circulating pump. The 'new' model was over $700, and was 2" shorter between the flanges on 1½" iron pipe. (Looks like this red one

There were no adaptor flanges, so it required removing a 2½ ft. section of iron pipe, replacing it with copper (price 2ft of threaded copper pipe)!, and THEN replacing the flanges, as they were not 'exactly' a fit....and the iron pipe required 2 men and a big pipe wrench and an hour of intense wrenching to loosen.....and to get the flange off the lower piece of pipe, it had to be removed and *I* had to stand on it while the plumber leaned on the LARGE wrench. There was about 4 hours labor total, and I watched most of it. (They didn't charge me for 2 trips to the supply house, trying to find the right parts.)