A bit late!
Indeed , back in the late 40's and early 50's there was heavy fighting between these two giants. But compromises were made, so one could say there were no losers, only winners. Back in these days the USA had, and still has, a very important industry: entertainment. So the industry served diners, pool halls and restaurants with music machines, juke boxes. And the smaller format 45's could be changed more quickly if the mechanism could place the record reliably on the turntable, either a normal platter ( AMI-ROWE and ROCK OLA) or some kind of vertical mechanism such as Wurlitzer en Seeburg developped for the new format. So one could say it was the juke box industry that saved the 45.....For normal use the limited playing time made it less popular for home use, but perfect for use in juke boxes. And, later on, for distributing hitparade records. That was the time the RCA changers became extremely popular with the public. In a way, these 45's were more flexible because one could stack different artists on the spindle, a 10 or 12 inch record played longer, but one had to listen to only one artist for as long as the side lasted. The juke box industry had another great idea, automatic speed change. This was done by using 7 inch records with a small hole. If the juke box detects the small hole, it either electronically or mechanically changes the rpm to 33. The juke box album was born. Sometimes 4 tracks per side. In Europe, the entertainment (far more traditional) industry was quite different, less outdoor entertainment and totally different habits per country. So that's what made the confusion what to use as standard. Initially, the 45's pressed in Commonwealth countries had the 7 inch with centers that could be punched out, later on they made solid centers only. For juke box use special records ( often different artists per side, not available for the public) were pressed with a large hole, Italy did the same. In Holland, there was a mix between records that had the large hole and those that had the removable center. Later on, roughly 1972 till the end, only the large hole format was used. In the UK and the Commonwealth, changers were very popular. And these were nearly all equipped with the small hole changer spindle and also featured the then still popular 78 format, hence the small hole adaption. So habits, confusion and very different lifestyles were part of the differences in formats. Interesting!