Not only that, it also goes the other way. If you're retired, you can't easily pick up another shift or do some overtime if you need to balance the budget, so the most available option for trading time for money is in finding savings.
And people always forget to account for taxes. Purchase prices are in after-tax dollars and hourly wages aren't. Between sales tax, state and federal income tax and government benefits phase outs from earning more money, the wage-equivalent value of saving a buck can be around double the nominal hourly wage.
And taxes strongly discourage trading time with others: I can't trade an hour of work with somebody else because my hour gets taxed and their hour gets taxed.
In New Zealand the marginal tax rate for the median earner takes more than 1/3rd of your wages. The top marginal rate is 39%. It isn't motivating!
All else equal, even if it takes you twice as long to do something (compared to employing someone), you are often better off doing it yourself.
And people always forget to account for taxes. Purchase prices are in after-tax dollars and hourly wages aren't. Between sales tax, state and federal income tax and government benefits phase outs from earning more money, the wage-equivalent value of saving a buck can be around double the nominal hourly wage.