They prob got a ton of back stock and manufacturing materials from IBM with the Buckling Spring and related rights purchase so it was easiest to stay with that for a time. Once they ran out they called up the cheapest sweat shop they could find and had them feed tin wire through a swizel stick machine to make their cables, which they permanently attached and even NIB ones are usually kinked. The swizel stick machine probably broke so they went to the next cheapest guy who had a round cable machine.
What Lexmark did to the Model M goes against the entire mechanical and vintage keyboard owning overkill-engineering concept so I don't buy Lex's, I stick to early IBM made Model M's. But that's just my view.
At least Unicomp did some original things. Lexmark should have stuck to what IBM engineered or done something different with the buckling spring switch.
With all that said, many early "good Lexmarks" were actually IBM keyboards, New Old Stock or parts that IBM hadn't distributed yet, you can tell by the devolution of their stuff, their labels, etc. got cheap over time but the early boards were like IBM's.
