I can't speak for the girl scouts, my girls want nothing to do with them.
Sadly, this statement is incorrect. The battlefield is shifting and BSA (national) is working hard to help its local councils to source much needed funding and make up for the decline in UW funding, which is only increasing.
There is much misinformation in the general public about BSA operating expenses and sources of funding. Basically, BSA works at 3 levels: (1) national council office in Irving, TX, (2) ~ 200 local councils, and (3) the individual youth units, i.e., Cub Packs, and Boy Scout troops chartered to various organizations - mainly churches.
The operating budgets of the local councils can range over ~ 25-60% dependent upon UW giving. There are ~ 1,300 UW chapters in the U.S. A council may have several UW chapters within its boundary. The council has to prepare detailed requests to the UW chapters to qualify for funding. Smaller councils may have to to take out short-term bank loans just to make payroll - I've witnessed that.
Most volunteers work/help at the unit level and make donations to help fund their unit(s). But $$$ is needed at the national and council levels to provide for (1) staff salaries, (2) property maintenance, (3) insurance needs, especially litigation, and (4) program development, e.g., all of the printed materials needed to guide volunteer adults and youth in achieving quality programs.