The standards are not all good for the same purposes, and many of them have problems anyways. Furthermore, you will not always know all of the details at first,

The standards are not all good for the same purposes, and many of them have problems anyways. Furthermore, you will not always know all of the details at first, and different computers will have differences than each other, for good reasons. Furthermore, people do not necessarily agree (this does not always break compatibility, but sometimes it does, although sometimes indirect compatibility is possible). This is some possible reasons why they cannot all be made compatible.