Sorry, but Wikipedia is simply wrong on that point. You can request fluoride treatments and children's medicine in "bubble gum flavor". But, no, that isn't simulating the flavor of unflavored bubble gum. It is simulating the default flavor of (many) bubble gum(s).

The default flavor of bubble gum is very sweet and quite strong and clearly fades as you chew the gum. You can taste unflavored bubble gum via "ABC gum" (already been chewed). It is not sweet, tastes nothing like "bubble gum" flavor, and can even be a bit unpleasant (varies by brand, IME).

And you would notice that flavor if you simply added "strawberry flavor" on top of it. Strawberry bubble gum does not have (much) of the default flavor added to it (depending on brand, it can have a note of (parts of) the default flavor so it tastes like strawberry with a hint of "it is still bubble gum" flavor).

Bubble gum flavor is indeed mostly composed of fruit flavors but is fairly distinctive. One approximation of the genre is 3 parts banana flavor 3 parts pineapple flavor 2 parts wintergreen, 1 part cinnamon and 1 part clove. Those flavors have very little to do with the base ingredients included in all flavors of bubble gum.

Sources agree that the original "bubble gum" (both the style of gum and the flavor) was Double Bubble. One source sums up the original flavor source nicely:

The original flavor of Double Bubble is a closely guarded secret and no one knows for sure of what it is composed. All we know is that it is a mixture of fruity flavors derived from both natural and artificial sources. Later, other bubble gum companies copied the flavor as best they could.