Fun fact: Some producers that use digital recording systems will mix in analog noise because the noise itself can be very pleasing in the right dosage. In this way it is used more like an effect rather than an inherent limitation of the recording process.
To quote Daniel Rutter: "[B]etter-mastered music will sound better on cassette than badly-mastered music would at a zillion bits per second."
The outer grooves have relatively more fidelity (needle moving faster) than the inner grooves, so the master may be progressively tweaked to add more high end as the content gets closer to the inner groove. The closer you get to the inner groove, the lower the playback fidelity.
12" Singles have larger groove spacing so you can slam them way harder than an LP. There is a greater margin of error and less chance of the cutting lathe skipping or hopping during cutting the master.
The process for creating stereo vinyl recordings is pretty much a compromise that allows stereo content while maintaining compatibility with mono playback equipment. This results in another series of compromises/limitations in the mix, like severely limiting the amount of truly stereo content. Extremely loud or bass heavy content that is panned wide would cause the cutting lathe to skip, etc.