I am not one to make a lot of comments on Forums but this discussion got my interest.
I honestly don't think SL is any different than when I first started. I think I was the one who changed [as I would expect to in any new venture that becomes more routine]. When I started, some things I would pay top dollar for, other things I only bought because they were cheap enough, and this has not changed. I do this in RL too.
So, from my point of view as a long time SL consumer (I used to landscape and stage land for sale), and then as a 3-year merchant as well....
At first I was super happy when anyone bought anything from me, now it is difficult to keep up with every detail. And yes, sales dip and soar depending on the season or year, but I have a sister who has an RL retail store mostly for tourists and that is pretty much the same ebb and flow as her retail business: she sells lots of small items [example: custom postcards] alongside sales of upmarket HOT items [example: fine cotton summer dresses or hand-painted fans] that she gets lucky to purchase from someone and it just takes off.
I truly don't think SL has changed, I think, it's us who change as we see it with different or new eyes.
At least for me, the secret has been to remember that SL is meant to be fun. I don't have to sell anything to feel happy and it's fun when I find a HOT item whether I'm buying it or selling it.... just my 2 cents.