Anyone who doesn't share sufficient business details when trying to garner investment or developers etc. is clearly far too inexperienced to bother with.
If you have stacks of money and can prove this large bank account then of course you can hire developers and staff at the going rate. If you want people to work for less than the going rate in exchange for stock options, or invest money, then you will have to give them every single detail on how the business will operate, what the market research results indicate, expected profit margins, sales figures, growth, competitor landscape, existing IP, fall back plans, time lines, partners, expertise, prior experience, progress, etc. etc.
Having a good idea is dead easy. Pretty much everyone does, and any developer or engineer worth their salt undoubtedly has several strong ideas of their own. Making a successful business out of an idea is incredibly difficult and hard work, and has a huge amount of luck thrown in. 90% of start-ups fail, and they mostly have good ideas. Some start-up succeed and have very bad ideas. A good start-up company could make chocolate teapots go a long way, an average start-up will see a free infinite energy device fail.
A developer that is rewarded with stock will want to know if your idea is better than his, and whether you have the ability, determination and energy to make it succeed. Are you going to work 70 hour weeks, give up weekend and holidays, travel across the country, work on every single lead, put your life and soul into every opportunity?
You are asking a huge commitment from employees and investors so you need to present as much evidence as possible on why you will succeed. Otherwise the develop will just work somewhere else where they are guaranteed a salary or a start-up they believe is more likely to succeed.