I do alot of weed wacking at my part-time job, Echo 225 is my favorite, but I started with an EGO and am glad I graduated to gas power.
I have found that 0.095 line does last longer, but transfers more impact to your wrist and forearm. The 0.080 line is the opposite. The thing you don't think about with each diameter is how it the larger line diameter impacts the ability to bump feed consistently. With an old spool of 0.095 line, I spend far too much time removing the line, rewinding because the line won't spool out properly. With a fresh batch of 0.095 it seems okay, but I swear it gets harder as it ages. Yes, I soaked the line in water and it DOES improve the situation but the best is still fresh line from the big box store. With 0.080 line I can wind more line into the spool, so the overall amount of work per spool is about the same?
The other thing is the 0.095 line is more likely to send stuff into your face and body. I wear shin guards and my legs are pocked from errant flying debris. Yes I wear shorts because it gets hot in SW Ontario in the lawn care season.
To the OP complaint, if you are expecting nylon line to withstand concrete or hard stones, you're using the wrong tool.