I thought for a while about this comment and I must say, I don't understand why you're so snarky here. The advice is actually not that bad.
The assumption is: A mostly unmaintained business has the risk of becoming obsolete rather quickly.
Better to have cash in the bank now than a potential income over the span of several years. Furthermore, tax-wise, it is cheaper to sell than to keep the business.
The question for every business is probably: Did the business reach its peak (under the current owner) and is it more feasible to sell right now or can it provide your above-a-certain-threshold income for several years to come?
The reduced tax rate for capital gains is merely a side effect, but could favor the decision to sell or not to sell in one direction or another.
Would you care to elaborate why the advice is so bad?
Because your hidden assumption is that business is worth having only if it is keeping you busy or that adding new features might prevent obsolescence.
What he has is something that hasn't been taking a lot of his time with a fairly stable customer base of people like me, who pay for the service because what is does is useful enough for me and not because somebody on the other side is working his ass off.
It is a widespread belief that you should add features to prevent users either getting bored with your service or to diversify into other groups. What is rarely appreciated is that new features are a cost that may drive current users away when they dilute a product. If you solve a problem well for a large enough group of people, it may be sensible to just step away from the keyboard.
Obsolescence is actually not the main problem. The problem is disruption: someone else comes along and offers a better product, or better value for money, or some combination of both.
