May be the NSA probably had this before IDA came about. It’s the NSA after all. They are now releasing it because it’s not a competitive edge anymore and can be used as a recruiting tool.
I don't think that is possible. I used early versions of IDA Pro on MS-DOS in 1996... and it had the core analysis and interactive disasm mode then. Ghidra seems to be based on this very concept, all the way down to the "XREF" labels. Even the sub-panels in the UI look the same: Imports, Exports, Symbols...