@verylate A few remarks.
Generally speaking, the Vienna Game was mainly developed as a device to selectively access those lines which were regarded as the most promising in the KG (with a XIX c. perspective), whilst avoiding or discouraging defensive tools such as an early d5.
Modern engine evaluation is different of course, but I would hardly call the Vienna Game "inferior", as long as you only play 3.f4 against 2...Nc6.
Several major defensive options for black are limited in their scope (e.g. 4...g5 can be met in a wide variety of ways such as Hamppe-Allgaier or Pierce which offer somewhat superior practical chances, compared to their KG counterparts).
A few wild gambits, like the Bertin (Three Pawns) against the Cunningham (1.e4 e5 2.Nc3 Nc6 3.f4 exf4 4.Nf3 Be7 5.Bc4 Bh4+ 6.g3 fxg3 7.0-0 gxh2+ 8.Kh1) become excellent even from an engine perspective.
Moreover, the Steinitz Gambit exists etc...
Against 2...Nf6 admittedly, the immediate f4 is very dull, but you already know this if you are trying to reach the Frankenstein-Dracula (which is not a gambit per se) instead...
BTW, you are correct. It seems quite difficult to have low level players take on e4 and go into the FD.
I had to trick a very inexperienced friend of mine into playing it with white, and we ended up following a famous(?!) game of Larsen from the '70...