^^ In general the way you couch your ideas here reinforce the idea that we're talking tendencies/strong leanings, not absolutes. (I know you know that, but some others might not based on the typical pushback you get, so I'm just summarizing it.)
So with your sports example, you give a decent explanation why it would be very unlikely for an INTP to excel enough to professionally play a team sport. Of course, what complicates matters is that humans are extremely adaptable/versatile, even when we have strongly rooted tendencies. And some of us are more malleable than others, again for multiple reasons. So perhaps an INTP would develop an interest in participating in team sports for some reason based on upbringing and not-as-direct motives.
But as you note it's still pretty likely they wouldn't be able to operate on the same level as those for whom it's a primary life focus. The mind tends to organize under some overarcing, guiding principles, and even these learned behaviors are organized under that umbrella; and this can determine the ultimate success of those behaviors. (So in this case "team sports" might not be pursued for its own sake but rather for an ulterior unrealized motive, hence leaving one at a disadvantage to those for whom it is actually a priority and thus a large time and energy investment. There's a reason why specialists do better in their field of focus than a generalist typically might.)
I think this is also the "black box" issue with typing folks. As you note, only behavior is observable (and behavior itself can stem from a multiplicity of sources), so we're forced to resort to probabilities and patterns that might explain the part of the system that we cannot directly observe. So when we draw conclusions, it's based on the assumption that we're talking tendencies and underlying cohesive patterns, versus absolutes.
Anyway...
...I found the hiking example enlightening, especially with my interest in it that I pursue far less than I think I should want to. (Example: Saturday morning: "I want to go hiking." Late Saturday afternoon: "Dammit, I wanted to go hiking, but I spent my time doing <this>, I better get out while there is still sunlight!" and then a 1-2 hour hike versus an all-day one. IOW, I thought I had one priority; but in the end I guess my underlying priorities were different after all.)
But now you've made me think about it myself. For me, hiking ties into the Ne/Si cog pair -- the Ne from exploring new pathways and seeing new things that others might not see ("world of wonder," I feel the same when I consider new countries to visit or interstellar travel), and Si because in my childhood getting out of my crazy dysfunctional house was a priority, so I associate it with fond memories and good feels. Wandering around the rural countryside was the only place in my childhood where I was FREE. The world was mine, I didn't have to deal with crazy people, I could go where I want and do what I wanted and it didn't matter who I was or how I looked or what anyone else wanted to impose on me because they weren't there. I was "pure exploration / pure thought" as I interacted with the world. But I'm kind of a prissy hiker; I don't mind getting soaked, scratched up/bloody, or taking a few bruises; but I don't like dirt or mud and do my best not to get muddy.
I think nowadays when I do hike, I enjoy it most when (1) I'm on a new trail and (2) I'm winging it and have to use my thinking skills to navigate / figure out how to get around obstacles. (It's kind of a less intensive form of rock climbing, an outdoor pursuit that I think can be directly positive for ITPs and seems to attract ISTPs with interest in the outdoors -- your Ti is anchored specifically into the world around you and you're making tiny adjustments every second to stay on course.) So I still do it; but I have to make a conscious committment to do so. i could be a very good hiker and climber if I invested the time, but apparently since my home is a "safe" undisturbed place nowadays, I end up doing things I want to do more there.