You say you understand, but your comment makes it sound as if you do not realize??I understand entirely how the media is moving slower due to the reduced radius near the center! My point was that while that is true, it does not affect the audio passband with modern styli because the cutter can easily cut modulation at 20kHz no worries. It most definitely affects it with the older 1960s-and-before cartridges about which scholarly papers that still get linked today are written.
The issue of inner grooves is a cutting AND playback issue. You focus entirely on playback and try to paint a Rosy picture. The inner grooves are always compromised, during cutting also.
That is why the last song on most sides is always a ballad or quieter number. Most mastering engineers reduce the level a bit AND reduce the highs to get around this issue.
Any issue in playback, (such as inner groove distortion or roll off of highs) has a similar but opposite effect during cutting.
The grooves are packed tighter and tighter as there is far less "Real estate" to cut the "Groove" and consequently the radius is smaller and it becomes harder to cut AND playback towards the middle.
Part of the reason for 45 Rpm records with only a couple songs.