Impressive looking token holders, I must say.
As for your analysis of your progress, I feel there is a parameter you might have missed.; How often does your collection get utilized for one of its purposes, or in blunt terms,
how frequently do you play?.
Having limited resources, including space, I have a personal rule; For
my forces, any army/fleet that I do not use at least
once a year gets moved to a list for disposal - Usually sale, sometimes gifting to other keen players. Pragmatically, this makes more space available, and b can bring in funds to allow me to explore new options ( Read; Buy new toys for a new game or update previous forces.
). In practice, this also keeps me flexible as I make a regular shift from force to force, rules to rules and play style to play style, so I keep mentally fresh.
That works for me, though might not work for anyone else. I confess I admire your approach here, though.