[morzh]

Well, if you remember the Capacitor Plague of the end of 1990s and beginning of 2000s, the electrolyte was the reason.

Rubicon developed the water-based electrolyte, which was much cheaper. And provided for much lower ESR.
This was important for hi-ripple/low ESR caps, that were lower voltages (below 100V) and were used mostly as the output filters in switching power supplies.
So the recipe was stolen, but the proprietary stabilizers Rubicon used were overlooked.

So, yes, today's electrolytes are different and in those Low ESR lower voltage caps they are aqueous.
The other electrolytes are different also from the old ones.