[TeMPOraL]

If you have problems with X that could be easily solved by Y, you don't buy device Z instead that makes problem X worse. People aren't that dumb. If they buy Z, they have some other reasons.

EDIT nevermind, I'm being stupid here. Too much coffee probably. Commenters below are right.

[jdbernard]

If Y is a strenuous activity (walking when very overweight), if the problems caused by X (obesity) are mostly long-term, and if Z is a device that offers immediate relief for X's short-term problems, then yes people very often buy Z.

People choose immediate gratification over long-term solutions all the time.

[chronial]

I myself just avoided walking for a few months, and I've seen quite a few people use aids that they should not use out of laziness. So I disagree with your statement.