If you want to get pedantic then clear text consoles are the core concept behind time sharing systems, the methodology behind Multics and UNIX, and thus pre-dates LISP Machines by decades (we all stand on the shoulders of giants).
But that doesn't mean there isn't still value in someone writing a new library and sharing it with the community.
Right, Time sharing wasn't implemented yet at that time, when Lisp was having its first interactive console in 1960. It was then also implemented on the first time sharing operating systems.
ok, let's put it another way, a LISP console is all well and good but systems in 1960 weren't yet multi-tasking (or at least multi-tasking systems in 1960 were still rare) so you couldn't have a LISP process running as one thread and query it's running state from another.
The reason I keep hammering on about time sharing is because they largely came hand in hand, time sharing systems needed to support multi-tasking whereas single user systems didn't (you still see echoes of this in the 80s with CP/M, DOS and 8-bit micros running BASIC). In fact if you look at the history of multi-tasking it roughly follows the same time line and lineage as the uptake of time sharing systems (around mid '60s IIRC). Before then you'd have to stop the execution of one program before you could start execution on another.
I know some "LISPians" like to think everything in computing eventually leads back to LISP but that's not always the case (and I say that as a big fan of the language myself).
One might just write a main loop, which takes Lisp expressions (or other input) from two or more different terminals and executes each expression interleaved. Those were not 'concurrent programs' which shared some state, but function calls within the same Lisp system, using an interactive execution loop serving several I/O devices.
An early (mid 60s) application domain would be multi-player games over terminals controlled from a single process.
Lisp also has the idea of break loops, which halt the current execution (for example triggered by some kind of interrupt), allow interaction with the program state and then let one continue the program in some way. Thus one would not need to attach a debugger I/O loop from another process, but the debugger repl would be a part of the running program and could be called on demand.
That you 'know some "LISPians" like to think everything in computing eventually leads back to LISP but that's not always the case' doesn't invalidate the fact that Lisp systems were running on many of the early computers & operating systems from 1960 onwards and followed their evolution. Thus at least some interesting stuff has been done very early in Lisp, too.
But that doesn't mean there isn't still value in someone writing a new library and sharing it with the community.