There is the production aspect, but surely not the railroads and levees

you seem to be mixing up the tech tree a bit there

Railroads requires Steam Power (also gives levees) but that requires Replaceable Parts which requires Banking... Once you've gone that far you may as well just research Rifling and forget the grenadiers.
The production aspect I see is the combination of drydocks, Iron Works and military academies. The way I leverage that group of 3 techs is; research Chemistry for frigates and privateers, followed by Steel for cannons, drydocks and Iron Works, followed by Military Science. So that can make a swarm of powerful privateers that will get you plenty of GG (especially if Imperialistic) which you can invest in military academies to boost production (each GG is can be worth 20 hammers per turn or 6 times better than a GE

). At the same time I will have anticipated the cannons arriving by building some trebuchets as that is really effective upgrade (only costs 80 gold) and anticipated the grenadiers arriving with some macemen with CR promotions and some crossbows with CG promotions. All you need then is a nice fleet of galleons and the world is your oyster
They are both useful military techs that can deliver the decisive edge if used properly in combination with a few other techs. Then the only thing that's dead at the end is the enemy