Concord grape pie is many things, but BLAND is not one of them.
I believe that the two times I’ve eaten grape pie (made by the same person) the seeds were just left in. It was fine that way.
I grew concord grapes back in the day. Incredibly intense. I can’t imagine eating a pie slice-sized piece in one go. It would be just too much.
Note that for canning concord grape jelly, you have to let the “juice” cool for a good while and settle out the bitter tartaric acid crystals. Is tartaric acid a problem for grape pies?
Well, if you want to bend the definition of “pie” until it deforms, you could argue that jelly donuts are super popular. But jelly gets super-cloying after a few bites, so the amount in a jelly donut may just be the right dosage, where a wedge of the stuff might be too much.
I meant grocery store grapes would seemingly be too bland. Not the Concord grape pie. I have never eaten one, so I can’t have an opinion on it.
My recipe for grape pie requires Concord grapes. But they are hard to find around here, in NE Kansas, so I rarely get a chance to make it. Maybe the scarcity contributes to a lack of commercial grape pie.
I have made them and they are a lot of work compared to other pies. But well worth it. Nothing like a perfectly balanced (sweet/sour) grape pie. I once made them from wild Concord grapes and that was the best pie I have ever had but twice as much work as the normal grape pie.
Dennis
I love tart foods. I make a rhubarb pie or two each year from our rhubarb, but I am the only one that will eat it since I use little, if any, sugar.
Would a grape-rhubarb pie be worth considering?
Not for me. But, as I say, I do add sugar to get the right level of tartness in the pie, as far as acidity goes. I’ve never had a problem with any sort of crystallization being deposited in the pies.
My favorite aunt used to make grape pie, the on!y person in town who did. It was wonderful! Next time I saw grape pie was up.in the finger lakes of New York. The detailed description from CalMeacham has me thinking “I can do that!” .Probably can’t and won’t but if I stumble upon Concord grapes somewhere, I’m going to give it a shot.
Sure! For obvious reasons, most combinations involving rhubarb are with something that’s known for being straight-ahead sweet, but I don’t think there’s any chemical or culinary REASON why grapes would be wrong. It might be great.
Reasons why this isn’t famous already: 1. Work. 2. It has rhubarb. 
I came across this same question today.