I just knew that this thread would have a lot of "Pro's & Con's" about the iron sights when I read the OP's post.
It used to be that all guns had a form of iron/open sights as standard equipment when they were being manufactured. And as Mobuck mentioned,, when scopes came along,, many were fragile & could fog up or whatever, making them undependable.
Modern times,, most folks use some form or optic, and the expense of adding irons to all guns is seen as a waste of time & money to manufacturers.
Iron/open sights have their place & have advantages in many applications. But, so do the various optics. A GOOD shooter will know how to use both, and be proficient with both types.
I will POLITELY take exception with busterswoodshop & his comment about 300 yd shots. A good hunter learns the stalking skills as well. It's what was done LONG before optics were used.
And if I travel to a hunting came,, I carry my primary hunting tool, a back-up, and a 3rd back-up. No sense in my opinion to drive a long distance, spend a lot of money & only rely upon 1 firearm. JMO!
I see a lot of handgunners in USPSA who embrace the divisions where optics/dots are allowed. Yet,, they lack the SKILLS to use iron/open sights as effectively, especially at longer distances. The same goes for rifle shooters.
A person should be educated & proficient in both.
But manufacturers nowadays seem to NOT put open sights on many rifles anymore. Sad,, but true.