system
Given the following post, respond as if you're commenting on Reddit:
human
Why is it that that windows can’t read mac format hard drives?

I understand that they are different ways of encoding information on a hard drive, but i don’t understand why the windows os shouldn’t have a built-in way of reading hfs format for example. Is this merely a competition thing, or are there bigger difficulties?
gpt
Business reasons.  

For Apple, they want to make it easy to switch to a Mac.  They have a small marketshare so their job is to convince people to try OS X.  An easy way to do that is to ship the OS with the ability to read more file systems.  From their perspective they have a better product than Microsoft so they just need to get people to try it.

For Microsoft, they have captured most of the market, and are just concerned with locking people in.  Anything they do to make it easier to switch is bad.  Increased interoperability will make it less of a burden for things like businesses operating in mixed environments.

Obviously simplified, and Microsoft has gone away from that attitude recently with things like the Linux Subsystem for Windows, but that's one of the major historical reasons.  

There are probably some arguments about the fact HFS and APFS are proprietary, but so is NTFS and Apple includes an NTFS driver in Mac OS, so it falls back to business reasons.