The thing is, a lot of people think that blue badges are handed out like sweets - they’re not. They’re very difficult to obtain and the application process involves getting robust evidence from you GP, as well in many cases, having to attend a medical at the request of the issuing authority. People who have fluctuating conditions will be required to provide evidence that they present for 50% of the time or more, so it’s properly assessed. And in my own experience, disabled people tend to be a lot more considerate. For myself, I’m in a wheelchair and if I can find a disabled bay at the far end of the spaces I’ll do so because it leaves the nearer ones empty for those with walking issues. I have a friend who has a walking disability and she will use the nearer standard spaces wherever she can so that those who need the wider spaces can park.
There are many hidden disabilities which conceal a walking difficulty too - for example, my partner has a serious heart condition and has a badge because it limits the physical activity he can do, including walking any distance, and disabled spaces allow parking closer to the entrances of places. You’d never know he has the condition from looking at him, apart from when he’s exerted himself too much and is gasping for breath. And people may have mental health conditions/Autism or ADHD for example, which reduces their awareness of danger, so parking safely and close to destination is important - again, you wouldn’t know this just by looking at them, so how do you differentiate when it comes to need ?
I also think a lot is down to car park owners. Supermarkets in particular will cram in as many standard spaces as they can and as a result the spaces have got smaller. I would happily use a standard space because in the wheelchair I can mobilise further than someone who has walking restrictions. The reason I don’t is because the narrow spaces make it very difficult to negotiate the wheelchair and get into it, and from previous experience, you can’t guarantee that when you get back to your car, someone in the next bay hasn’t parked too close for you to actually get back into the car.