I'm know I'm a bit late to the party, but most of those apple trees produce an apple that really isn't pleasant to eat straight/raw. They tend to be tart and hard. Now, they are good for cooked/baked goods like pies. Cooking them helps convert some of the matter into sugars to dissipate the tart nature of them. And with them being firmer than your typical store apple, they tend to hold together instead of turn to mush.
Lots of those trees were planted to have a supplementary food source(pies), or to make cider/wine from. ...and to feed livestock.
You'll be surprised if you bite into one and expect it to be as tasty as a Red Delicious from the grocery store.
We still have a couple of those trees on our farm - planted in the early 1900's. Our oldest tree died about 15-20 years ago that was near the house, so we had to remove it. It was planted in the second half of the 1800's when the farm was established. Once every couple years I'll go get some for the old lady to make a desert with. I like to occasionally cut them in quarters, trim out the centers, then put them on the grill and baste them with honey, brown sugar, and cinnamon. I'll throw some soaked apple wood chips on the coals to add some smokey flavor to them too.