It depends on what you mean by robotic mowers. If you mean motors that drive the wheels and you don’t have to walk behind them (or sit on them), yes, these exist without any cloud service. However, if you mean autonomous, then I don’t think those are here yet. The non-cloud robot mowers use human held remote controls.

I can think of one that is autonomous and doesn’t require the cloud for operation, but does require the cloud for the inital setup and mapping. Once it has the map loaded in, it doesn’t need an internet connection.