The blue badge only applies to the highway and not private land.
It’s the same as people parking in parent and child spaces nothing can be done about it, unlike if you do not park in a bay correctly or overstay the often 2 hr time limit or park where your not meant to. Then they can take action for loss, not issue a fine a such. You can be issued a fine on the highway if you break the rules. like parking in a blue badge bay without a badge or one that has a specfic number plate.
Where it make a huge difference is the ability to park on a single or double yellow line with no double loading lines on the kerb for 3 hrs.
I do get your point but more and more blue badges are being given out than ever before and no more spaces are being provided. So sometimes when companies only have a few bays then it is an issue but at Tesco they have a huge amount of bb bays maybe 40 or 50, where as at aldi there’s maybe only 10.