Admiral shares are a function of the Vanguard mutual funds themselves; if you're buying the underlying companies directly, "admiral shares" don't matter, since you're not paying management expenses at all.
Vanguard isn't a non profit, which is an organization that in contrast to a for-profit company, has no obligation or goal to increase share holder's value.
Vanguard is a company like any other for-profit, with the distinction that Vanguard's own shares are being held by the funds it manages, so increasing fees, e.g., would probably decrease share holder's value.
2. Without Vanguard(and other index funds), you do not quality for admiral shares.
3. Vanguard's fees are among the lowest(last time i checked it was between 0.1-0.5%). There is no charge for buying and selling Vanguard funds.
4. Vanguard is non-profit.
~I am no way affiliated with Vanguard.