I lost count on my wally world point beach after 3,500 miles and she is on her fourth engine. I would be shocked if it was below 4K but couldn't prove it. The fenders of course would have failed with out shoring up and the book rack was rattling off.
Just replaced the rear brakes and both rims/wheels. (Front wheel with drum brake/wheel from Worksman) They blew out side ways. (both) But this is after thousands of miles and am testing a prototype engine that I am trying to beat to death to see what it can take. I am not offering an opinion but the 2 wally world bikes I have had held up amazingly well. I had meant to replace the cheap, plastic wheels from the day I purchased them, lol. Both were so out of true at the end, they were hitting the brakes on both sides at different times. (I was gonna get to it! ((some day)) She had the heart break of seriosus and the dreaded "Wibble-wobble"
Both rims blew out at the seams slowly and I had plenty of advance notice. I am using them to learn how to lace wheels. The bearings were fine and would put them on other wheels.
Just my experience with em. Aside from fenders, I would feel fine after selling Walmart MB. As long as I either assembled it or stripped it down and reassembled. This particular PB came assembled and only one brake was right out of 4 and not every thing was tightened down well.
Given the opportunity, I rather build (for sale) with a tag sale, thrift store old steel American or European bicycle. Can find some great engine candidates for very lil cash with lil more need then some maintenance. But have no problem with the wally world bikes.