I beg to differ on the 78 rpm. Records cut at higher rpm's can achieve higher fidelity. Sort of like the difference between 7.5 ips on reel to reel and 3.75 ips on reel to reel.
Also the 10 inches gives the record cutter more room for the grooves.
If you buy some of the 12 inch 45 rpm singles, you will get a good idea of the sound you can get. That's why the club dj's use 12 inch 45 rpm singles.
I suggest you try an experiment. See if you can find a 12 inch 45 rpm single of a song you like. Then compare that to the album version of the song.
You will hear what I'm talking about.!