I wonder if my problems with GTS go beyond GTS, and are more so with skilled match-making as a general online mechanic? I think my largest issue is that I don't feel like I'm seeing progress, and I think that's typical for games that use skilled match-making. I'm not asking to get matched with completely unskilled players for easy wins, but as it stands, I don't feel like improving pays dividends.
I think you're not seeing progress because you're looking at the wrong information. Keep a record of your lap times at various circuits in various cars. Draw a line through it every time there's a game update with any physics changes or BoP changes. Keep an eye on your stats at
https://www.gran-turismo.com/gb/gtsport/user/ paying attention to your personal performances (again, keep a record) rather than your comparison to the community.
Remember that this game is in it's later life stages. That means lots of established players practising regularly and few new players. It's likely that you're improving - but so is the rest of the racing community, so your relative standing is not changing much. To see your progress you'll need to keep an ongoing record of your personal stats.
Relative stading is further skewed by available practice times. If you're 20 something, living in your mum's basement with nothing to do but drive 10 - 14 hours a day, you'll likely improve relatively quickly (months rather than years). If you're mid-forties, holding down full time work, have a social life and a family, you may only be able to race / practice five hours a week. The first guy is driving 10 - 15 times as much as the second, his younger muscles/nerves train quicker and his performance improvement will reflect the different circumstances.
Except for the very top semi-professional / professional e-Sport drivers who not only are able to, but are obliged to practice most of every day and do it with a coach at hand, relative standings are meaningless because it's not a level playing field. To see your own progress you need to monitor your personal performances (
lap times, NOT finish positions) and you need to do it in combination with a record of game updates that may affect vehicle handling and performance.