The phrase "oil bandwagon" refers to the growing popularity or acceptance of using oil as a resource or fuel. It implies that people or businesses are jumping on the trend of using and relying on oil. Full definition
The WAPF was the only organization out there at that time recommending cod liver oil — almost everyone else in alternative health related fields was on the fish oil bandwagon. (thehealthyhomeeconomist.com)
Turns out this guy I've been dating uses it for just about everything under the sun, so now I'm joining the coconut oil bandwagon as well (ericamesirov.com)