Well, thanks Heathpack, for the nice words, and putting nice words in my mouth

So here's what I took from the original post:
"Some places I ride, I am one of the fast people on Strava, and other places I'm one of the slow people. How come?"

The tl;dr version of my answer (as above) - you're using the wrong ruler to measure yourself, so don't bother.

My take on it is that use of strava doesn't necessarily represent either the general population of cyclists in an area or the people you might want to actually compare yourself to, and on top of that, it doesn't even really fairly represent competition in that one place, because conditions change.

Some places will have adopted the Strava culture more - more technology, more high speed internet, more access to and interest in tech tools like GPS/Garmin bike computers, more money to spend on those things. The self-selected population of people who use strava isn't going to be evenly distributed across the cycling population everywhere. It's not going to match the distribution of cyclists. Bay Area - everyone has a Garmin. Boulder - everyone has a Garmin and a power meter. Milan - I dunno. Middle of nowhere in rural Italy - I dunno. Majorca - everyone is a pro, and you are at the bottom of the leaderboard. Middle of nowhere in India - I have really no idea. Africa? Probably lots of KOMs out there for the taking.

Trying to compare yourself on strava is pretty pointless, as Heathpack pointed out, conditions vary, population adoption of strava varies, population adoption of cycling varies.

If you want to know how you rank (which is what I read as the most salient point of your question) - you have to go compete directly. On the same day. In the same race. Even the time recorded isn't really a good measuring stick - what about drafting? Wind? I barely every use Strava, but I have a QOM from a ride I did in Arizona when I had bronchitis and asthma and couldn't breath and could barely pedal. Does that mean I'm the fastest chick to ever ride that stretch? Hell no, other women on the trip I was on were leaving me in the dust, but they didn't post it on Strava.

So - pin on a number, or resign yourself to the fact that your ruler isn't calibrated and is therefore worthless.