I don't see anything to be gained by wondering why the past standards were different. However, I'll try to answer some of your questions.
(1) The old Standard T and P of 60 °F and 1 atmosphere was primarily used by the USA, the worldwide petroleum and natural gas industries, and others who still used the set of English or Imperial units.
(2) The old Normal T and P of 0 °C and 1 atmosphere (i.e., 101.325 kPa) was primarily used by those nations adhering to the SI metric units and by those chemists and physicists worldwide who adhered to the old IUPAC definition of standard conditions.
(3) Then in about 1997 (I believe), the IUPAC changed their definition of standard conditions to 0 °C and 100 kPa (i.e., 1 bar). Why they made the change, I have no knowledge.
(4) Now, in recent years most of the worldwide petroleum and natural gas industries have changed their standard conditions for gas volumes to 60 °F and 14.73 psia (which is slightly more than 1 atmosphere=14.696 psia). Again, I have no knowledge as to why that change was made.
(5) No, the gas law constant R has not changed nor is there any likelihood that it will change. It is a fundamental constant and it is not dependent on any set of Temperature and Pressure.
(6) No, there is no new Normal T and P. As I've been saying in this thread, there just is no set of standard conditions that are universally accepted any longer. We must learn to always state what reference conditions of T and P that we are using when we communicate with each other.