Lobby your lawmakers. Banks have no incentive to provide open APIs.
For example, in the UK banks did nothing until they were forced to - the market regulator now requires the nine largest banks to provide an open API (https://www.openbanking.org.uk).
The law doesn't restrict the banks giving access to non-AISPs and, like you say, many of the modern banks do have personal API access, it just sets a minimum bar you have to reach before they're forced to let you in. It seems like a pragmatic middle ground.
What is bad, in my eyes, is the law currently only applies to the CMA9.