The Black Powder book – especially if you buy it at discount on Amazon – is not unreasonably priced as a hardback, full colour illustrated book. But it contains so much that one would not actually use while playing a game.
In 'the good old days' wargames rules were slim pamphlets that contained the rules and nothing else, because it was assumed – correctly – that players would acquire their historical information, uniform details, modelling and painting tips elsewhere.
The current fashion, which I too deplore, is to pad rules out to make a full size book, with background information, illustrations of figures or games of a standard few readers will be able to emulate and other superfluous material. But we seem to be stuck with it, because a lot of wargamers seem willing to shell out for such glossy books, and the publisher of a set with a much smaller page count and lower production values will fear it will not be able to compete in the marketplace.
The examples of DBA and HotT, however, proves that an innovative, playable set of rules can succeed, despite an eye-straining font, convoluted, legalistic language and a complete lack of colour pictures – though perhaps the reputation Phil Barker had gained from WRG rules helped to sell them at first?