'98 La Sabre - repair or replace rocker panels?

I have a '98 LeSabre in excellent condition except one thing, due to being resident in the rust belt, and -- I fear -- a possible flaw at manufacture (what should be sealed not actually sealed): the rocker panels on both sides are beginning to get visible rust bubbles.

What seems to be the best local body shop says that the rocker panels cannot be replaced, but that they can squirt some sort of rust-stopper into what should be the closed space within the unit, then refinish where the bubbles are, paint, and hope for the best.

This sounds very stop-gap and impermanent to me.

Does anyone have any better ideas? It seems a shame to let a very good and very good-looking car go to seed just because of this.

Correct the rockers are part of the major side panel. They could be cut out of a good car and sectioned onto yours but this ia a major job. They could be sectioned with new sheet metal, but again this is an expensive job, my shop does this all the time here in upstate NY.

Correct the rockers are part of the major side panel. They could be cut out of a good car and sectioned onto yours but this ia a major job. They could be sectioned with new sheet metal, but again this is an expensive job, my shop does this all the time here in upstate NY.

Thanks for the info. Any ball-park guess as to what the cost might be?