What i can say to this type of conversation; -is that a couple years ago, i was still using Cable Ethernet connection speeds at a very basic price package, and on a Gaming PC with a decent network card, i usually always ran into an array of loading/texture/sim issues.
Fast-forward to today, I've upgraded to 250mb Fiber internet on the very same Gaming PC, and I've seen tremendous differences (improvements) overall since I've returned to Second Life.
I don't know how much of what i just typed can be extrapolated as useful or constructive, but for me personal, my bottleneck all these years appeared to primarily exist inside my internet connection speeds.