if 10.7 mhz 455 khz
These IF frequencies were standardized when AM and then FM broadcasting was introduced in the USA. 455 was chosen because it was below the 540 end of the AM broadcast band. The 5 on the end was because mixing products of stations spaced 10 apart would not get into the IF and the local oscillator radiation would fall between stations. Once this was used, the frequency assignments were made so that local strong signals would not have a combination of IMD frequencies that fell in the IF or be at the image frequency of any station. Another consideration at the time was what high power stations were in that frequency range that would leak into the IF.
On the FM band, the 10.7 is high enough that the image is out of the broadcast band. Since stations are spaced 0.2 apart the mixing products would not fall in the IF and the LO radiation will fall between stations. Cost of components etc kept the frequency from being higher.
In both these cases there was an economic regeneration cycle where the more sets were produced with these IF frequencies the lower price the components for them were which made using something different more expensive.