Only so many companies were making IF transformers. For whatever reason, the tuner industry standardized on two IF frequencies, 10.7 mc for FM and 455 kc for AM. I suspect that was pushed more by the transformer makers than the tuner designers just to make life easy. Either way if you really started looking into all this and found the cross numbers for various tuners I suspect you'd find that many of them cross reference to the same part numbers.
To be honest, there are only so many ways to pull in a signal. If you look at any superhet tuner, its going to look very much like any other superhet tuner. The only real variables are the bandwidth of the IF transformers and the detector style in use. I suppose the limiter stage also factors in there somewhere.