It doesn't work that way. Fungus spores don't have even the minimal cognitive ability that insect pests have or any ability to choose. They go where the wind and rain take them. They're not going to gravitate toward "trap crops" the way bugs might.

If you leave diseased plants in your garden, that just makes it likelier that your new plants will get diseased sooner, as it increases the amount of inoculum circulating in your garden.

The fact is, fall crops are very prone to disease because the spores, etc. are already in your garden. Your best bet is to choose resistant varieties and/or spray fungicide regularly and often from the first day you plant out.

What are "your sources", BTW? I'd be curious to see exactly what they're saying.

I see a flaw in the plan. Tomatoes are sensitive to cold and will slow down when it gets down in the 50s at night. I would adjust expectations accordingly, say 30 days prior to first frost. The shorter days and cooler temps will lock them up pretty good, though they will ripen, it will be slooow at the end.

Gorbelly, I wouldn't say I have a specific source, and I can't remember where I heard this from. I believe I was watching a YouTube video on "Gary Pilarchik", where he was doing a July garden tour. He showed a few young tomato plants that he started in which he then stated that sometimes have young plants in the garden, and planting at different times can make up for loss to disease and fungus early on in the season. He said that while the older ones are beat up from heat and disease, the younger ones will sometimes chug through and produce late.

Sounds like he's talking about succession planting, which is timing planting so that younger, more vigorous plants are available to take over for older, more worn-out plants.

And I wouldn't succession plant indeterminate tomatoes. A lot of people do it with determinate tomatoes, as determinate tomatoes tend to produce a big, initial flush of fruit and then produce very few fruit after that, so succession planting makes sense in order to always have plants at any given time that are producing a lot. But a true indeterminate tomato takes a while to really start producing well, and once it does, it should produce fairly steadily until it dies from frost or disease. It's better to try to maintain good growing practices WRT fertilizer, water, and disease prevention/management to keep the plants alive and producing until frost than to succession plant indeterminate tomatoes. Unless you live in an area with a long spring and fall and extremely hot summer (see below).

Another thing that he might have been talking about, if he lives in a hotter area, is having 2 seasons. People in areas with a very long frost-free period and very hot summers often plant very early and have a spring tomato season and then re-plant with new plants for the fall because high summer for them is too hot for tomato plants to set fruit, and the heat and disease pressures can make it hard to keep the plants alive until the weather cools down in the fall.