Many of the regranting organisations were/​are largely volunteer run. EAA only hired a part time staff member to do accounting after ~4 years running and moving $1m+ per year (now at ~$4 million p/​a with still <1 FTE).
Pretty much every major EA org I can think of started volunteer run while people were working/​studying. CEA started on the back of Giving What We Can & 80,000 Hours which had been mostly volunteer run by students/​academics.
Many of the regranting organisations were/​are largely volunteer run. EAA only hired a part time staff member to do accounting after ~4 years running and moving $1m+ per year (now at ~$4 million p/​a with still <1 FTE).
Pretty much every major EA org I can think of started volunteer run while people were working/​studying. CEA started on the back of Giving What We Can & 80,000 Hours which had been mostly volunteer run by students/​academics.