The usual answer to your question is usually too much nitrogen applied but I can tell you that I had the same problem this year. I planted 3 "Tumblin Tom" tomatoes in a half barrell and they bloomed abundantly but yielded few tomatoes.
I really believe that the temps were too hot for pollination to occur. I still have them growing and will see if they produce any fruit now that the temps have cooled down.

Yes, that is the usual answer--too much nitrogen. But as mentioned, all my plants get the same fertilizer, in the same dose, and I use an organic 5-5-5, and very little at that.
I don't think weather is the culprit either, we have had a cooler than normal summer.

I think the correct answer is - sometimes it just happens!

Three years ago I had a Mortgage Lifter that grew to 7 feet or so but never set one fruit. All others produced lots of tomatoes.

So swore I would never plant another M. Lifter, but this year low and behold happened to see a nice specimen at the local nursery. Bought it, and long story short it was my best producer this year.

Moral of the story - sometimes stuff just happens, and it's impossible to know why.

There are such things as "bull" plants, sterile plants. But the most likely explanation other than excess nitrogen - and yes it is possible for one plant to get too much while another gets too little - is weather.

Timing is everything when it comes to fruit set. Timing of the feedings and timing of the heat, humidity, and water relevant to blooming. All can contribute to plant stress and a stressed plant sometimes just won't set fruit. It's a survival mechanism. ;)

Dave

Guess I will just have to give this variety another chance next year. Maybe I got a bull plant, maybe I just got a plant that was weird. I don't think it was anything in the environment per se, it just "happened" like gman says.
After 15 years of tomato growing, I guess one incident is pretty lucky.
Thanks to all who took the time to reply, appreciate your thoughts!