I mean, while it's NOT the players fault, don't we already know that all the extra stuff on well established characters adds load to the servers? I've posted about it many times over the years, from years of personal experience multiboxing. Yes, it's just one data point (me), and anecdotal, but from what I've seen in game, yes, older characters with more stuff related to them (larger banks filled with more stuff, filled bags, many past lives, etc) does seem to cause more load than a first lifer with not much stuff. Not no load at all, but not as much.
The anecdote which has been reoccurring for me for many years now is that my main account is vip, has overflowing banks and many mules, large TR caches, many past lives on more than one character, and years worth of accumulated stuff. My alt accounts have very few characters on them, and those ones are mostly first lifers, and barely any collected junk between them. I run them at the same time on the same computer, and use windowed mode and multiple monitors to see more than one at the same time. One of them suffers much more lag, slowdown, loading screen freezes, etc than the others. Consistently. For many years. I bet you can guess which one it is (it's my main with all the stuff).
Again, this is not to say it's players fault. It is not. The game infrastructure is clearly unable to handle what the game encourages us to do long term. I'm hoping there is work being done in the background to eventually resolve these (and many many other) issues, but I didn't think it was an unknown thing. Though I do believe we should continue to bring it up / talk about it, so that the devs get continually reminded that it is an issue and don't forget / sweet it under the rug as so many long standing issues seem to have been.