I bought some gear because it was cheaper to buy the gear I needed to record the project I wanted to do, than to rent a studio, and not really know how long it would take to record. You could spend hours getting something right and have to watch the clock and spend a fortune on studio time.
Well, once you do one project, you do another, and you buy a little more gear and so on. You read the recording books, you listen to music in a different way. Not the licks, but the sound etc.
Once you get into it, you then want a better recording space etc.
You start reading the studio mags etc and you get inspired.
Also, as a professional musician myself, I'm on the road a lot, and want to be able to earn money locally while i'm off the road too. A home studio is a great way of doing that.
I play mainly solo guitar instrumentals, which has a limited audience, but I'm not selling out. This is what I want to play.
With a studio, I'd totally be okay selling out, because it wouldn't be me having to perform commercial songs.
I'd have fun producing/engineering, but not touring with it under my own name. Once it's done, it's done with.
Also, I own the studio. That means that I'm able to help someone out if they have no budget at all for an album. If they're a musician friend that has no dough, I can record them for free and do them a favor, and get them started.
A cd or at least an album of MP3's to download or whatever, is essential in getting gigs today. A CD is almost like having a card.
Having a studio give you absolute freedom musically to do any project with no constraints and no time limit.
Technology and manufacturing techniques in the last 15 years or so has enabled companies to produce studio gear that is affordable to the consumer.
So, the musician consumes.....