That's a very negative view of why people want to share on Strava. It's not all about ego. Sometimes it's about motivation, in two ways. I try to track my own times on various segments to see how well my training is going, and sometimes challenge myself to beat those times, because that helps me increase route variety and that helps me keep going. (I don't actually like running so much as I like having run BTW.) Garmin Connect's equivalent of segments is a barely populated wasteland by comparison (though I do like the pace-color-coded display more than Strava's so I usually look at both).

Even more importantly, Strava is a platform where friends can encourage each other, and celebrate each other's accomplishments. I greatly appreciate the "kudos" I get from others, and that was especially true after I had a setback some years ago. I have a friend right now who had an even more serious setback, and I'm glad I have a way to support him as he logs his rehab activities. It's the only forum where we're connected (he's not very online the way I am) and it enriches both of our lives.

I know a lot of people think Strava is just about getting KoMs to satisfy ego. I submit that it's often projection or bitterness from people who don't get what they want out of it. Seems like a miserable way to be.