Originally Posted by Bassdogs
The short answer is because they come with the RV. It escapes me that the RV industry that has created all kinds of reliable and creative features for their units, can't design an awning system that is capable of standing up to moderate rain and wind. Truth is IMHO that rv awnings are basically worthless unless you are sitting in your site and are reactive to changes in the weather. When you have witnessed the aftermath of an awning left open during a light but gusty wind you can then draw your own conclusion.
We love our awning and it is out almost all the time we are camping, except when a heavier wind or heavy rain is expected or happening. We feel that it about doubles the size of the "living space" of our camper, which is a 24 footer with no slides. We have an outdoor mat, and a portable outdoor kitchen, grill/stove, table, etc. that we set up under the awning. We do a lot of living out there and it keeps us in the shade when the sun is very hot, and it keeps us and our stuff dry when it is raining (put not heavy downpouring).
With most awnings being about 16 foot long or longer and something like 8 foot wide, that is a HUGE surface that acts like a sail to catch wind. Exactly what do you want RV manufacturers to do? You can install de-flappers and anchor tie-downs to the awning, but nothing is going to prevent that sail from catching a big wind gust.
For us, we would MUCH rather have our awning knowing its (somewhat minor) limitations, than not have it at all.