It could be good to keep in mind that it might be difficult to measure your progression when you’re primarily measuring it against yourself.

Speaking from the perspective of competition against yourself instead of competition against others: Looking at others is easier, you see what they have and what you don’t (for certain comparisons), but to know if you’re moving forward requires an active effort if you're competing against yourself. It requires some form of quantification that otherwise comes automatically. I suppose it depends on where you are in life and if you've yet to settle, but I might be blind about what I’ve achieved at times because of what I’ve yet to accomplish, and by not comparing myself to others I might lose the ambition to progress faster than I could.

In any case something like “progression through collaboration” as you describe it seems to be an organic solution to the problem of looking too much inward as well. You compete with yourself but don’t forget to look to others for inspiration and perspective on how far you’ve come.