Instead of spending thousands of dollars to fix the wiring, another option would be to spend hundreds of dollars installing GFCI outlets at every outlet instead of protecting the whole circuit with a GFCI breaker (or upstream GFCI outlet)

But if I had wiring that was leaking enough current to trip a GFCI, I'd rather find the fault in the wiring.

When I rewired an old house, the livingroom circuit kept tripping the GFCI breaker. It took a while to find, but apparently at a junction box, the bedroom circuit was connected to the livingroom neutral, so that neutral was connected to 2 circuits and was potentially overloaded.