Most furniture from 30+ years ago is broken. The older it gets, the more likely it is to have been broken. For your grandparents (and the folks they passed it on to), it means: You were able to have space for the table all the years, and didn't move into a place where it didn't fit. It means it didn't have accidents. Do you have chairs that came with it - or did they break too (very common)? If you do have the chairs, are they sturdy enough for a child to climb on and wiggle in? (many aren't).
It means they didn't have a fire or break the table when moving it (if they moved over the years).
It means they could wax it and so could everyone else. It means they could do repairs when needed. It means that it didn't rot despite waxing.
It means that you (and/or other family members) also had a space for it: If you bought an old piece used, it meant that there was an avenue to sell it.
And a bunch of things like that. 90 year old furniture isn't the norm, and can hardly be used to verify that older things are made better (and besides, they had some cheap stuff too).