That's a complex question. First of all, few if any quilters can justify such a purchase financially. It takes time to build up the skills and clients thay start to pay back your investment.
What you can get out of it in fun and growth is dependent upon what you want it for. I know many quilters that have purchased a long arm, and just use it for their own quilts. If you can afford that, great go for it.
However, if you want to eventually do quilts for others, and are willing to work through the tough times financially, you can make a living off of it.
Its an investment in your future, if you can afford the original investment.
Whatever you do, good luck,
Lanny