Published projects often are 10-30 and more years old, when BJTs ruled.
Still, MOSFETs tend to be a little bit more expensive for the same rating. As a switch, the more affordable ones need up to 10V on the gate to fully turn on. This alone kills a lot of projects. MOSFETs are much more easily damaged by static electricity than BJTs.
BJTs work at lower drive voltages, and more people know how to use them.
I guess MosFets are decreasingly killing projects. Their RDS(ON) is getting lower even at low gate voltages.
Here is the datasheet of the IRF7401 for example. That one offers an ID of 4.1A at VGS of 4.5V and RDS(ON) of 0.022Ω. At VGS=2.7V ID is still relatively high at 3.5A with an increased RDS(ON) of 0.030Ω.
The only downside: It comes in an SO8 package - not great for beginners.
I use it to operate solenoids for the shutters of an ancient camera to make it usable for high speed films.