Why isn’t there Microsoft Access for Mac ?

the underlying core of the program runs on services not available on Apple devices. this is also why it doesn't work on Linux.
but i can't imagine why you would WANT it. MySQL is FREE, does all the same stuff, and has been in use on the internet by over 75% of websites for a very long time...
plus it is universally supported by ALL platforms!

Because not enough people use Access to make it profitable for Microsoft to spend the time and money needed to create a MAC version of the program.  Most people and companies have gone with SQL for their databases rather than Access.

There is no Microsoft Access for macOS because Microsoft deems it a competitive advantage not to make a version for macOS. If people are dependent on Access, they cannot switch to macOS.

Access is basically an interface for the legacy Jet database. It was introduced around the time of Apple's 68K -> PowerPC transition, which is probably why Microsoft never ported it to the Mac platform. And since Microsoft has been in the process of deprecating it in favor of Microsoft SQL for years, it makes no sense to port it now. The only way it would be beneficial was if you have been running a Windows-only business since the early 90s and have suddenly switched to a Mac-only shop. And even then, you could have migrated the database to SQL.

Because Mac is it's own thing.  They're going to start making their own cpu and gpu soon.