Nowadays Windows is filled with adware and is fairly slow, but it wasn’t always like this. Was there a particular time where a change occurred?
A switch to linux can be “painless”, depending on the usecase of the user. I’m (learning to be) a web developer, which can be done on literally any OS, so if I were to switch to linux now and not 3-4 years ago, the switch would be pretty painless. But everyone has their use case and linux just plain does not work for some of them at the moment…