Toggle???

Toggle a whole environment and intrepeter's behavior? Do you know how much architecture that would involve? That's like trying to tell IDLE to be able to both delete or keep your variables on exit, or the JVM to have a toggle switch for memory and garbage management.

Why doesn't the developer make themselves useful and simply write a save function that freezes their buffer variable values to a text, json or SQLite file that they can read from or stream rather than trying to set back a whole community years of progress in an effort to accommodate perhaps entitled or lazy devs.

Can you even imagine the architectural costs of trying to accommodate streaming data and timestamped data as opposed to you just writing your own stuff to file?