With the way incentives are set up right now, there’s no reason to. For all practical purposes, police are completely immune to any consequences of unjustified killings– DA’s never ever prosecute cops and internal affairs departments are do-nothing bodies designed only to make it look like there’s some accountability– so there’s no reason to not always use the maximum amount of force “just in case”.

Tasers tend to have problems with clothing and distance, CS is easy to deal with if the person is trained, and bean bags are ineffective against large targets.

Non-lethal force is useful in cases where the police have no reason to believe the other person is armed. It works sometimes but often it doesn't. Police and military are even trained to resist non-lethal chemical attacks like CS gas very successfully. When a person is armed with contact weapon like a knife or club, non-lethal is usually only used when a lethal option is in place.

Exactly. Surely we can figure out ways to incapacitate without killing. There are already options (eg tasers). If for some reason the existing tech isn't effective enough, well then too bad, that's what you get until we invent something better. Take all that govt money pouring into militarization of police and instead use it to innovate in non-lethal methods.