There's an obvious elephant in the room here which is not discussed. 10k hours might let you master something (and even that claim is questionable like others h

There's an obvious elephant in the room here which is not discussed. 10k hours might let you master something (and even that claim is questionable like others have mentioned) but why do you need to be a "master" to switch careers? Being better at (say) web development than all the other people in your company that have other skills immediately makes you valuable in a specific way and starts your career shift. You can build up on that over the years. There are ways to reconfigure your life other than by "Switching". More gradual ways to ease into another career exist and can be worthwhile. Everything comes with a cost though so make sure you're willing to pay it.