EVGATech_LeeM
Actually, people definitely prefer to have 80Plus certified power supplies.  I agree that price is always a question for people, and what people are willing to pay for different ratings and features vary by market.  Around the world, some markets prefer to have very low-priced Gold-rated units, but don't need all the features like modular cables, passive cooling, etc.  However, they still want the higher efficiency that Gold or higher-rated units bring.
 
In the past, people simply didn't have options for PSU efficiency.  Most of those power supplies were anywhere from 55%-75% efficient under most loads.  These days, the lack of an 80Plus rating generally means that units are cost-down, cheaply produced units.  Yes, they still need to comply with state, federal, and (if applicable) international safety testing, but there is still a difference in quality if they lack a rating, and a higher failure rate would be expected.  Remember, Bronze isn't the first level of 80Plus certification; 80Plus certification starts at power supplies that are 80% efficient, mostly known as "80Plus White", even if white technically isn't the certification name.
 
What you're paying for at 80%, Bronze, honorary mention for the short-lived Silver power supplies, Gold, Platinum, and Titanium units is both efficiency and a reduction in heat produced by these units due to increasingly better efficiency as you go up in rating.  It's not a straight correlation that the internal components are necessarily better at Bronze and Gold, but you generally can't make a more efficient unit without spending at least some effort on topology and component selection.
 
Ultimately, it's the extra efficiency and perception of greater quality that people prefer.  If you can run your system with anywhere from 10-25% less power at the wall, you will save more money over time than if you purchased a less efficient unit.  Similarly, the additional quality that you pay for with higher 80Plus rated power supplies translates into fewer issues and fewer potential issues the longer you hold onto that power supply.
 
The odds are always in your favor that you may never run into an issue with any piece of hardware electronics.  However, using non-80Plus rated units these days generally means that you're using a power supply that is probably a lot cheaper for a reason, and that reason could be due to lower quality components, lower-end topology, and potentially suspect capability among the various protections that the unit may claim to have. 

revollucian
I have been using Bronze rated for about a decade as well.. never really encountered any issues, although that might not be the case for everyone. Features reflect in price though, and its down to the type of system you want to build. Fully modular PSUs for example are really cool but more often than not they're a bit more expensive, Gold+ ones may have better safety features built-in that protects your system in the long run and protects the PSU as well. I'm going to guess that a Bronze PSU will have a shorter lifespan on average than higher rated ones.