If you buy a roll of rewire and have someone make cages for you they will last for years and years. Each cage would have to be staked and you would have to have room to store the cages over the winter. How many plants do you normally have?

Doubling down on the concrete remesh suggestion above. It will last a literal lifetime. You don't have to bury any part of them and the "holes" are just the right size.

To support them, the same hardware store department gets you two or three foot long pieces of rebar. Three eights or half inch diameter are reasonable sizes. With any sort of hammer, bang half way into the ground on each side of each cage. Won't hurt tomato roots one bit.

Fasten the rods to the cages with anything: wire, cable ties, etc. You can get 400 feet of easy-to-twist iron wire for four dollars in (yep) the same department.

The t-posts are already in the ground, so why not get a panel of fence or trellis or something and attach that between the t-posts, and then you can tie the growing stems and the suckers to that?

I agree. The FL weave is very crude.
The posts / stakes are placed on a straight line (roughly) and then woven.
If you put tension on the twine it can choke/cut the tomato stems. . If you leave it loose then the branches may fall down longitudinally.
So if you want the FL weave to work, need to have 3 sets of post/stake in parallel ..Alternatively one can install short cross bars on the T-Posts.
This way you can really weave .

Sey

CRW cages CRW cages CRW cages oh and did I mention cages? :) Lots of posts with pictures here about them. Much more expensive alternative - Texas Tomato Cages - also lots of posts with pics here about them.

Dave

I make cages out of 3/4 PVC pipe. They last forever and are very sturdy. And they're a lot easier to work with than CRW. No gloves or wire cutters needed.

Here's what they look like in action.

Here's a link in case you're interested on how they're made.

PVC tomato cage page