I started learning to program in the 3rd grade. From there, it was a hobby. Come time for college, I decide I don't want to do that a job because I don't want to ruin my hobby.
Fast forward 10 years, and I finally decide I need a career, not a job. I look at my skills and decide that programming is the only one worth doing.
Turns out, I love programming more than ever now! It was absolutely a mistake for me to try to avoid it. I'm better at it than ever, and I can do more things than ever.
I still, sometimes, do it as a hobby. So in that respect, yes, it kind of killed my hobby. But I have that fun at work now, and I get to do other hobbies at home. It's a positive thing all around.
The key is that my job isn't the soul-sucking variety. I work in a positive atmosphere and (mostly) on projects that I enjoy. I'm valued, and my employers prove it by paying me what I'm worth as well as having great benefits.
From time to time, I say that 'the worst thing I've done was to turn a hobby into work'.
It it not strictly true, there are worse things I could be doing instead. But I have lost some of the that initial spark.