Imo. Focus is the remedy.. I have a careful gameplan that is working (so far) :
1 build is an early mtb, building to catalogue spec
1 is a proper mtb to scare myself in the woods
1 is a hack
1 is a retro ride for the road
I have a similar rule.
Then 1 of each Ti, alu & steel combined with 1 ea of rigid, front susser, and full susser.
Therefore I only have an alu full susser left to get.
Oh hang on what about fixies, ss and road bikes .... Uh oh!
I started off with a similar game plan.
As I already owned a 94 Zaskar LE, I thought it would be great to own a handmade steel bike from the same era, as they were far beyond my reach at the time.
I started reading up and searching and was lucky enough to win a Roberts DB on ebay.... but it needed some work, so off it went to Roberts. While it was away I spotted a Roberts White Spider... then I chanced upon a Yates Diabolo, and then........ Well you know the rest.
And then of course there are the road bikes....
"Try not to punch any clowns"