Sorellina,
It's great to have the one who ranks close to, if not the queen to tomato growing adding her knowledge. And I mean that a a compliment.
But I need to add some anecdotal evidence about why heirlooms are becoming popular. First, though, I will add that at least in my area, there are many more people growing their own veggies this year, which seems to be a nationwide trend. The last stats I read said that backyard gardens have increased by 28 percent over the last three years.
Anyway, about heirlooms - it has become the late '90s buzzword, like "staycation." Not so much much among experienced growers, but over the last two years, I'm amazed at the number of people who say they only buy heirlooms, I ought to grow heirlooms, is this an heirloom tomato before they buy the plant. It's like - well, if this is an heirloom, it must be great. That's BS - Belgium Giant is an heirloom and it tastes like crap. all it was good for was getting lots of juice!
But in selling plants I did notice that lots of people who did not buy from me was because I didn't have the plants they've been growing, their parents grew, and their grandparents grew. Conversely, my biggest seller was Siletz (which is an heirloom, though it has only been around for about 30 years, max) but no one knew it. I sold it as an very early-season variety, with fruit that is 8-10 ounces, has very few seeds. The people I have talked with that have ate the fruit claim it is one of the best tasting maters they have ever had.
To add to the confusion, there are lots of Russian tomatoes that are classified as Heirloom but aren't. Seed traders/collectors *presumed and believed* they had been grown for decades only to learn they were genetic mutants Russian scientists developed to grow in their conditions.
My advice is for anyone who wants to grow tomatoes is to start with ones the vast majority of people highly recommend plus add one or two types that sound interesting. Research the plant and its ideal growing conditions - what grows great in Ohio may flop in Georgia or Texas - heirloom or not!
Mike