I have just bought a similar setup, mid 90s taiwanese machine with an Anilam controller so I had similar thoughts around what if...
If the controller does die, you could probably find spare boards etc on ebay or similar.
If that doesnt appeal, you could probably convert to Mach controller, you already have servos, screws etc, so would need a PC, the Mach software, servo controllers and a breakout board.
Not completely straightforward but Mach has been used to control anything from sewing machines to massive gantry mills.
I am new to this myself but hope this helps.