That's not very smart because batteries are terrible! Most of my electric portable appliances had their battery die on me or decline significantly at some poin

That's not very smart because batteries are terrible! Most of my electric portable appliances had their battery die on me or decline significantly at some point and since many were either: 1) not replaceable or 2) replaceable with an impossible to find spare, I had to dump whole perfectly working items (except the dead battery). This could be mitigated if there is a standard battery format but for many reasons it will oppose good engineering for each item.