think you might be misunderstanding why apple bought the service.
it would have nothing to do with trying to get users to migrate to apple platforms.
it's about buying the service and using it to augment the existing weather tools within the apple platform. the app will not exist anywhere in the near future. it'll be integrated and shut down completely.
you could pour scorn on the original developers for selling out. but maybe the apple stock they got in return made them forget about the customers they previously had.