The clunky full bolster is relatively new. Maybe 1880-1940 for the golden age of the non-clunky bolster?
- French at the turn of the century had beautiful, very thin and precise bolsters--so nicely made and something you don't see on contemporary knives (or even post-war knives!).
- Solingen knives from this period also had thin and crisp bolsters (though usually thicker/wider than the French knives). Also really nice.
- Sheffield knives often had half-bolsters like a ferrule. I'd suspect that this was a borrowing from tool-making (think the bolster on a good chisel) because Sheffield was a center for tool and cutlery production. Some old early-1800s Sheffield knives have bolsters. AFAIK bolster appeared on French/German knives later.
- Some 18th-19th US and UK knives had bolsters/ferrules of poured lead/pewter. These had some cool taper/keyed shapes sometimes, but were added after and weren't part of forging.
As
@GorillaGrunt said, keeping the bolster at a 45-degree angle at the bottom got it out of the way of sharpening and, practically, god rid of any chance to dig it into the board. Nearly all of the nice examples of old nogent Sabs (and other French brands) I've seen had this. I think the old German sharpening style differed (though can't say definitively, as I haven't seen enough old Solingen knives to say for sure). The bolster would be brought up to the same height as the edge and then the bolster would be thinned/convexed, like a clamshell. This way, as height is lost through sharpenings, the bolster doesn't widen (just like the reason for thinning an edge after repeated sharpenings).
My thinking would be changes in industrial production in the 1800s made a forged bolster easier to produce on a large-scale--and also as a way to improve on the poured bolsters of the time. Maybe 1880-1940 for the golden age of the bolster?
Then, post-WWII manufacturing and tooling gave birth to the clunky bolster--maybe different drop-forging techniques or maybe just less time spent on refining the bolster through grinding? Also, this would coincide with the increase of an export market to the US post-war.
Regardless, if you can get a nice old example--French or German--with a thin bolster and crazy distal taper, you're in for a treat. There are usually good restoration candidates on the bay, and IMO grabbing one and fixing it is $50 well spent.
I think everybody should have at least one good old nogent sabatier (turn of the century), a good old Henckels, a good old Sheffield carver, and a good old US (Conn or Mass) carver (turn of the century).
So nice to see the different ways of making knives, the handwork, etc.