How can money be siphoned off? Miner fees?
Are you seriously admitting you are blind?
1. Selling the ICO/pre/instamine to you.
2. Using control of a significant portion of the coin supply (and thus perhaps 90+% of the exchange volume float) to buy coins from themselves, set fake bid/ask walls, and otherwise manipulate you into buying high and selling back to them low. Repeat & rinse.
3. Having some "governance" scheme wherein some staked nodes (e.g. Dash masternodes and Bitshares' DPOS delegates) pay out some of the created-out-of-thin-air coins for each block and pay them to the owners of these staked nodes, which are disproportionately those who control the coin supply from #2. And even paying some of these coins to the lead developers via "voted on projects" (and remembering who controls the staked nodes and thus who controls the votes).