If you like the speakers and want to keep them, there are some things you can do as described above to keep them going another 30 years.
If the tweeters have ferrofluid, it's worth refreshing. FF gets thick or dries up, and affects performance.
Parts upgrades are worth some consideration depending on the parts they used originally, and depending on your system, abilities, and desire to do so. Caps from the 90s tended to last longer than caps from the 50e/60s, but there are a lot of excellent grade caps available now. Cheap sand cast resistors and iron core inductors can also be upgraded with wire wound non-inductive types and air core inductors....stick close to original values. Cheap speaker inputs and junk wire can be upgraded too. You can replace push on connectors with direct solder if you go this far. You can also bypass fuses and circuit breakers for better sound. This is also a good time to check stuffing, bracing, insulation, etc. Each of those are pretty subtle as stand along upgrades, but doing all them can have a big impact, and kick the performance up a notch or two.