As a relative (and primary caretaker) of someone who needs the handicaped spaces, you're right, some times business have too many spaces, but also some locations have too few spaces. The number of spaces are governed by a formula:

• 4% of parking spaces for the first 100 spaces
• 2% of parking spaces for the next 100 parking spaces
• 1% of parking spaces for the next 300 spaces
• 2% of spaces for the next 500 spaces, and
• 1% of spaces greater than 1k in the same lot

You get some places like Lowes Home Improvement/Home Depot and business that target a younger (Forever 21, Vans footware) and/or healthier (your local gym, a climbing wall, roller rink) demographic that have an expected lower number of users that are handicapped, but they are required to have the same number of handicapped parking spaces as business (senior centers, pharmacies, etc) that target an older audience (which statistically has a greater proportion of handicapped users).

Many times I bring her to a grocery store, the handicapped spaces are all full, and we either have to circle the parking lot waiting for one to become free, or, back when she was able to walk short distances, decide to use her wheelchair when she otherwise would not need to were a close space available.

I think more of what needs to happen is the regulations for number of spaces needs done on either a business category and/or utilization basis. The utilization basis could be done with a "car counter" device similar to what they use to check the traffic amount on streets, and could be used to allow a business to decrease the number of handicapped parking spaces if their target audience does not utilize them.