CFIgigs
Interesting that a US question is being answered by UK FIs, a CFI being a Chief Flying Instructor here. Traditionaly, FIs receive very low remuneration and few make a viable living from it. Most is historical and reflects how the industry has evolved over a number of years. Some countries such as France regard recreational flying as a club activity where club members give their services as instructors for no remuneration at all. With a decline in the number of PPL applications, 50% over 21 years, the requirement for FIs has reduced whilst the cost of obtaining the qualification has risen steeply. There is no easy progression from a recreational instructor to a commercial instructor in Europe any more so the long term prospects do not look good.
Maybe you wil get some feedback from your US colleagues, but this is a predominantly UK forum.