I would question the seed source and fertility. A couple of years ago I had good tomato plants, started from seed (Johnny's WI 55 organic) but one plant had no tomatoes. The rest of the plants produced well but one did not. It was green and healthy looking like the others but no tomatoes. I expect quite a bit of variability in plants grown from heirloom seed, some better producers than others, that is to be expected. This should also give a bit of nuance to the population, some liking that growing season and some not as well. We have been very warm here this summer, one of the hotter July's I can remember. I did not put out my transplants until June 18 this summer, had my first ripe tomato yesterday, August 25. The seed package says 80 days for this strain of WI 55. I count 69 days for this first tomato. Started late, maybe my best transplants this year, very warm, a lot of biological fertilizer and water and looking to be a very good crop. The WI 55 love to send out low runners in August, I trim them back. I also cut off any new blossoms once I have an adequate fruit set and put the energy into finishing the tomatoes.
Tomatoes here need a lot of fertility to really produce. I use pelletized chicken litter, gypsum, copper, zinc, boron, hard rock phosphate (TBR), potassium sulphate, liquid fish, Soil Biological and compost if I have it. Water deeply and not so often, watch the plants and check the soil for moisture. Mulch early on to hold moisture and keep tomatoes off the ground. Tomatoes want full sun throughout the growing season.
My garden with TLC and lots of water has done well, the row crops in the area are poor due to lack of rainfall. Fargo, ND has had 8.89" to date (June 25), normal is 16.70.
some liking that growing season and maybe some not.