But I think there's more than what immediately meets the
    eye, and just going into an unsexy business for the sake
    of going into an unsexy business is not a sufficient
    condition for financial success in one's business.

Warren Buffet built his fortune on top of Potato Chips, Dumpsters, and Trailer Parks.

I agree that there is "more" to this than just going into something unsexy. But a key part of business success is differentiating yourself from the competition.

If you have no competition, then you win by default. Finding unsexy jobs that need to be done (ie: Payroll) gets you customers.