Development startup mechanism...?

i see business plans in fields of service and trade; but seldom you will find somebody trying to create something, -not just buy in one place and sell in the other. so i wonder how this happens in real life. let's say you have studied the market and there is a shortage on some device... for reference an electric meat cutting device (i know there's lot of them but i take it for reference). and to build one you need minimum 1 electronics engineer because it is related to electricity. 1 mechanical engineer which knows how to develop housing and setting all the mechanical parts. and 1 marketing specialist who knows how to present it to the market. let's add more 1 specialist in electronics because you may not find a universal all in one man who knows everything. a single specialist may know how to transform electricity well, but not know how to develop an onboard processor and communicate to the touchscreen.so you need one more guy who specializes in that. in short this kind of easy plan grows to ~5 persons. how would you propose your idea to somebody who's about to finance it? -like "hey i'v got an idea i'm planning to do this by these men and i need money for 1 year salaries and to rent space and more money to buy laboratory equipment " ....sounds very foolish. i'm cycling into my head what can i cut down, but even if it goes down to a single specialist. it will sound pretty much the same way -"give me the money and maybe it will work after 1 year". nobody would even listen. so, if there is 0 chance to convince somebody to finance you. -then how the hell should anyone start a business ever????? i'v seen here and there some businessmen offering 5000$ or so to invest in innovative ideas. but inventing and development is very time consuming thing it takes months and months to make it work 5000$ will not be enough for anything. if a single man, spends 90% of he's waking life at work or in the way to/from the work to earn for living, then he has no chance to do it by himself. back in the days people used to cut my word and answer "WORK HARD AND YOU'L HAVE IT! YOU DON'T WANNA WORK WHY DO YOU DEMAND!" -buuulshit, you do will work hard, and have a bread on the plate that is the truth. on top of that add the fact that universities are the scam, and books will never teach you all the secrets and "know how" about how to manufacture a device. one might spend tens of years in experiments to find it by himself. only once on some forum i have offered to create a group of enthusiasts to share knowledge and develop something together and people just attacked me. that i was planning to use everyone around and later throw them or something in short they filled the forum by such comments that any reader would momentarily get convinced that i was the source of evil there. well you might say that it is all impossible but remember how blizzard corporation started? 4 friends locked up in a garage for a year one even borrowed food money from he's grandma 15 000$ and in the end they created a multi million dollar company so... here i get lost. can anyone give me any hint how this possibly could work...? ...because even on a theoretical level all the possible combinations look failed right in the start.