We have found that the ACs they installed in homes tend to fail in less than the 10 years. Almost everyone around me has replaced theirs this year. We are at the 10 year point. Apparently they bought cheap ones.

AC out again
 

I don't know who you are referring to but cheaper units do exist that will fail sooner than one would expect. It's not that the units themselves are built any differently than a more expensive one, rather it is the protection control devices that are added onto the unit which will lengthen its life.
A residential central A/C unit is listed as a major appliance and as such has a certain life of 14 years...

We have a new home and they installed Carrier "Comfort" series - essentially their lowest cost system. Our previous home had a top-of-the-line Bryant Evolution system (rebranded Carrier Inifinity). While the system performed great, it wasn't exactly reliable. Over the course of 9 years, the following failed

-2 compressors
- condenser fan motor
- weld in condenser coil - was repairable but all R-410a was lost
- evaporator coil
- 2 defrost boards
- start capacitor
- 2 User Interfaces (the "thermostat" is called the User Inteface and it is really a computer)

Fortunately it had a 10-year parts and labor warranty. The Carrier "Comfort" series in our new home can not be any worse. So far, we have had an out-of-balance condenser fan replaced.