This is interesting as my understanding is my Grandmother, Mary Rydberg was his original employee keeping his books. She was still taken care of financially somehow after the bankruptcy sale. A stipulation of some sort.
My understanding was he was with him in some business function all the way back to 1949 when she was 28.
She told my mom (still alive) once, that Bill's greatest regret was getting involved with Sears. The money back guarantee almost put him under as people rode bikes and Go-Karts into the ground and Sears took them back no questions asked. Bill asked my grandmother what he was suppose to do with all these [machines].
Per Grammy, they continued to beat him up on prices. The final nail to the coffin being the go-kart recall. They beat Manco down to the point their quality and safety were compromised. Very similar to what they did to Emerson Electric on their radial arm saws. Emerson managed to bail on Sears (per a Emerson employee of the era). Manco, not so lucky.
Early 70s, our Schwin scramblers were stolen
Grammy wanted to give us either Go-Karts (dingo?) or mini-bikes. But nooo!! My parents didn't like that idea even though we could ride them down a dirt road area 5 houses away.
Instead, we got a pair of silver colored big old honking manco bicycles. Big rectangular seat, big shocks, heaviest bicycle ever. I swear they sent us big mini-bikes without motors. I had to push the thing uphill, on trails downhill, pretty hefty smooth until I went over the handlebars and that beast landed on me.
Yes, Manco made actual bicycles. No, they did not sell well. Yes, I regret not getting the Go-Karts.
-Adam
hwin
I remember drooling over the Manco Dingo Karts. I was trying to fix up a Dune cycle Me & my Grandad found at a swap meet but that was long ago & far away... 
