There are many different grades of mowers. A cheap residential mower is cheap and lasts just long enough that you don't think it was junk when you have to replace it. A commercial mower is used more in a month than most people mow in a lifetime and is built to higher quality (and price).

The neighborhood mower would cost 10x as much last just as long and serve the needs of 20 people - so a better deal in the long run. However what price are you willing to pay to not have to use the mower on your neighborhood's schedule - owning your own is probably worth it for you.