30 yr old speakers- time to replace drivers?

The Xovers are totally worn out ,having upgraded Xovers a long time the capacitors dry out for sure after 15 years or less , you loose detail and then uneven output per speakers ,then just stop working.

I agree, I would not put money into a thirty year old speaker. There have been huge improvements in every aspect of design.

Crossovers can last waaayyy more than 15 years. Hell I just sold a 50 year old sansui 9500 that would put the majority of integrated amps under 5k to shame. I know it’s not a speaker. Original caps other than a few small input caps replaced. If there’s nothing that sounds “off” I wouldn’t mess with it. 
 

upstairs system has original Paradigm Studio Monitors. Same thing 30 years old sound awesome, lacking no where compared to my main system downstairs. 

That said I am also with others if they need some work I would not put much into them if anything.

Degradation in SQ with rubber surrounds is brand and design dependent. I do not know your speaker.  In a vacation home in Vermont I have a vintage system used for background music, with 1981 DCM TimeWindows, with rubber surrounds.  It has been published that the drivers in this brand and model have longevity. There is no change in durometer of the rubber or SQ of the speakers from my experience. However, they sound like 1981 vintage speakers, through good ones for their day.  If needed, I would not invest any money in them even though they have sentimental value. There has been so much improvement in speaker design and SQ at all price points that I would go new.