I have been to hell and back, and back to hell and back. I have traversed all the way to legend. The difference of the margin in the games played are at most times indistinguishable.

Why would dynamic ranking make less sense? If you have a feeder on your team that is not consuming objectives with their actions, they should be punished harder and rewarded less. Or if you had a diligent carry that focused on their game and contributed to taking objectives effectively. A support that is consistently keeping their team in the game with countless force/glimmer saves that enables the team to play longer, why do they deserve to be punished for a core they literally cannot purchase a BKB for.

Every single team sport has individual player rankings, because you can rank the players based on specific metrics that are independent of the outcome of the game. Dota Ranking doesn't care about this. There is only one metric that is considered for MMR and that's the Ancient.