manicmike

Could just be changing trends. Black may not have been the, ahem, 'new black'. The '50s was when Singers other than black started appearing. Guess (really a guess) it's also when they moved from Japan to enamel paint, so having different colours would have been possible and easy. The tan ones would have been more popular initially, since they're different which would make them more unusual and thus desireable. Black ones would have started to seem a bit yesterday, but again, a complete guess.
I love the black ones, and the reason I didn't use my awesome aluminium 201p was that it was tan (looks a bit plastic and cheap). Its macho "get on with it" attitude has won me over, of course. Also have not one but two green 319k machines. Love them but would have loved them more had they been black. Perhaps I'm a sewing machine racist as well as a sewing machine youth hater - those young machines can get a real job, and a haircut while they're at it. Plastic whippersnappers!