The 1/FL rule is only a guide and has only ever been a guide as it depends on a number of factors and these other factors that are to be taken into consideration are:

1) How large you are going to print/view the image. A small image from just about any camera viewed on your phone screen can look sharp, but when you enlarge it to the size of your computer screen it may look quite unsharp and blurry depending on the image. This is where the "myth" about the new very high Mp cameras needing higher shutter speeds needs to be put to rest. The fact is, a high Mp camera will not look any worse then a low Mp camera when viewed at the same size and all other things being equal, ie physical camera sensor size (FF compared to FF for example), aperture, shutter speed, lens used , ISO etc. Where you may need to employ better camera technique and possibly employ higher shuuter speeds is when you decide to usitlise those extra Mp's and are going to display the image larger than that from a lower Mp camera or where you are going to crop significantly. It is only then that you may detect camera shake more so than from a lower Mp camera. However, you may have been able to hold the camera well enough for that not to be an issue.

2) Whether you are going to crop your image significantly when compared to a lower Mp camera. However, if you need to crop the high Mp cameras image, then you'd also need to crop the lower Mp camera's image the same amount to have the same resultant subject size thus making them both look just as blurred as each other.