Disclaimer: this is only comment - not advice.
The traditional business model is much as outlined. Get some product, invest in making it shiny and buy marketing. This is all about risk and the risk is usually reduced if you play safe, i.e. Pathfinder presents an almost exact copy of what was known to be WotC's already fairly successful 3.0-3.5 model in terms of the site, the artwork and the product lines.
While the risks/ costs can be reduced by simply re-gearing an existing successful business model, it's necessary to out-shine the original model by having a glossy site, artwork, products, marketing, possibly licensing and support. Costs and risk stack up there - but you are buying instant access to media love. Your products will be reviewed, blogs and forums will announce them and so on. That in turn may generate sales greater than the costs.
More recent model is the chop shop, where you use e-publishing to mimic a brand or product line - but don't pay out on production or marketing. This is reliant on replacing budgets with time and effort. You do your own proofreading, your own editing, your own marketing and probably only payout on artwork, (through up-front Kickstarter money or fairly inexpensive commissioned artwork). This is a re-brand or stick close to the original model approach, where lower pricing can offer players low-hanging fruit that they may pick-up in passing, e.g. an adventure with a cool cover for $5. The sheer amount of effort required to juggle everything often impacts on quality with the chop shop, so products may not have a long-tail.
There's a third way, but it blurs the distinction between hobby and business. The minute you say you're willing to depart from standard business models and experiment, rather than re-brand, the risk on any investment goes through the roof.
You can go ahead and take this approach to craft products as you wish to; but it's no longer a case of going to a bank and saying 'this product is exactly like this other selling product - if I run it efficiently I'll be able to make so much cash'.
Many of the first RPG companies started out along these lines, but the niche wasn't so crowded then and costs were kept right down pretty much until the hardback 1e PHB appeared.