My businesses have only had one or two suppliers. But I'm also not a successful business man so...
I don't think that's true. I don't know what your businesses are, but I'll give you an example of our business.
Most gold used today is gold that has already been mined over the last 4,000 years of gold mining. There are thousands of companies that recycle and refine gold. There are also thousands of companies that mine precious metals around the world. Then mints buy the refined precious metals and produce coins, rounds, bars, etc. They sell the final product directly to us in bulk or to large dealers, banks, or dealer networks, who then sell to us in bulk. All of these companies are our suppliers.
We also need paper, shipping supplies, printers, computers, phones to communicate with our customers. Hosting company, servers, web developers, and pens (we go through a lot of pens). Fridge/microwave and bottled water for our employees and anyone who comes by. Just to name a few of the things we buy for daily operations. All of these products are purchased from suppliers.