I think it's simply a matter of knowledgeable token collectors being very thin on the ground. At a rough guess, for every 1000 collectors of
US coins in America, there would be only 50 world coin collectors, and just a couple of token collectors.
"Tokens" is a very, very broad category - even broader than "coins". You've got Colonial tokens, Hard Times tokens, Civil War tokens and store cards, modern tokens, sales tax tokens, transportation tokens, and lots more... and that's just in the US series; every country has a different story with regard to tokens native to it.
This complexity is one factor in making token collecting less popular than coin collecting. There are other factors. Tokens, by definition, are usually not issued by a country's government, central bank or any other official body; this alone accounts for much of the bias against tokens from mainstream coin collectors. This lack of "official-ness" makes tokens seem "less real".
In regard to your first question, there are (relatively) few books put out on tokens, compared to coins, but they are out there if you can find them. The book put out by Krause Publications is
Rulau, while
Jaeger is the token companion to the
RedBook. Some books are dedicated to specific series; the "US transport token book", for example, is
Atwood-Coffee, while you need
Smith for non-American transport tokens.
But tokens are still very much a "front line" area for numismatic study; for many tokens we simply don't know who issued them, where or why. Since tokens don;t have an "official" government issuer to ask, if a token has little or no information about itself on itself, token researchers don't know where to begin looking for answers.
As for value, like any other object, a token's price is determined by supply and demand. "Supply" for tokens is usually quite low, but demand (as we have seen) is even lower, so the price stays low. Many tokens are as scarce as genuine 1804 dollars, but if practically nobody knows about them and nobody wants them, they'll stay cheap as chips.
I'm afraid I can't count myself among the experts in tokens. Not American ones, anyway. Ask me about Australian, British, New Zealand or Canadian ones and I'm on firmer ground.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis