Having said that, you have to include your on-site management (people and project), various other cost drivers (taxi or car costs, for example), domestic PMO and architecture oversight, and accept your delivery-days overage due to timezone and distance factors. In addition, those latter factors, plus a few regional-culture aspects, tend to result in needing more people (devs, supervisors, etc.) per function point than a pure colocated dev team. (Whereas a Mexico or LATAM team, while more expensive per developer, tends to be more agile for US-based projects due to timezone if nothing else.)
Cheaper? Per developer, absolutely. Solid development chops? Sure. An unalloyed win? Not without its caveats, but definitely worth exploring.
Salary for a top individual contributor engineer in the Bay Area (full stack), outside of specific skillsets like ML/AI, will top out around $200k.
Midwest, someone with the same skillset would probably make $125-150k.
I'm looking at Levels.fyi and at Google you only start to break $200k salary at L6 (Staff Engineer).