I just don't subscribe to a one size fits alll repair.
I cater to each area , and replace as needed. It may not be as profitable as what you are accustomed to, but it doesn't cut unnecessarily into a nice car where unwarranted. It is on a as needed basis only. BUT if cutting every time gives you the warm fuzzies than ok.
That is what cutting out that small piece out is doing, catering to the area. Every job is different. I don't replace entire sections or panels if it's not needed. Using mig wire alone in the rot holes as you suggested is not going to repair that area. The metal is rotten and thin, there is a piece missing and those holes larger than pinholes.
You are correct, one size does not fit all. Each job gets evaluated and repaired accordingly. This is not about profiting or doing more than is required at the customer's expense.
Tubes are galvanized
Never seen that before! Only parts I thought were gal on these cars were the headliner attachment strips, floorpan plugs and the wiring loom cover/carpet support at the door openings.
Rockers are galvanized, so are the door jamb supports.