Well that depends on the reason for the falls. If we enter a deep recession rates get cut which pushes bond prices higher thus anchoring a portfolio. They absolutely do work its just people are basing everything on the last 10 years of 0% rates. Of course the only way from there was down in prices and up in yields.100% VHVG (developed world)
I don't consider that aggressive, I consider it the safest thing to do.
Emerging markets increases fees and risk for seemingly no benefit.
Bonds are still garbage. Returns are below the base rate, price falls, doesn't hedge against stock downturns.