Wanted to add a reference here to the wikipedia, which claims this is a myth[1]:
> Despite popular belief,[2] there is no clear evidence that this was a deliberate design feature. When the original patent application was filed in 1933, the inventors described the key objectives as providing a screw head recess that (a) may be produced by a simple punching operation and which (b) is adapted for firm engagement with a driving tool with "no tendency of the driver to cam out".[3]
> Nevertheless, the property of the Phillips screw to easily cam out was found to be an advantage when driven by power tools of that time that had relatively unreliable slipping clutches, as cam-out protected the screw, threads, and driving bit from damage due to excessive torque. A follow-up patent refining the Phillips screw design in 1942 describes this feature
> Despite popular belief,[2] there is no clear evidence that this was a deliberate design feature. When the original patent application was filed in 1933, the inventors described the key objectives as providing a screw head recess that (a) may be produced by a simple punching operation and which (b) is adapted for firm engagement with a driving tool with "no tendency of the driver to cam out".[3]
> Nevertheless, the property of the Phillips screw to easily cam out was found to be an advantage when driven by power tools of that time that had relatively unreliable slipping clutches, as cam-out protected the screw, threads, and driving bit from damage due to excessive torque. A follow-up patent refining the Phillips screw design in 1942 describes this feature
[1] https://en.wikipedia.org/wiki/Cam_out