I ran into this concept with my neighbor; he wanted a U47 - but they cost SO MUCH money! He was balking, saying "I know it will actually bring me business, but will it be enough to cover what I'd have to spend?"
I mentioned that he had found SIX RCA-77 ribbon mics over the years that rarely got used more than one or two at a time. He sold a bunch of them on ebay and was able to afford the U47! And it brought in business... definitely a selling point for the studio.
So - what can you get rid of? Either to find something that will make your recordings better - or bring in work?
(Mine is compressors - I have a bunch of great ones, but very few preamps and mics.)
Just a quick note, and I point this out in my article this month, having a marquee mic, like a U47, will bring more business than a clone. Rightly or wrongly, that is the reality of a major market town like LA.