Do a segment of work some big company does
Specialize in a segment of someone's business, and make that part of business better. For example, if Fivrr is a site for side hustles, you can provide a section of their work and offer it better. Build a website that specialize in one of the operations of the big companies and cut across several companies. TSMC and Foxconn specialized in manufacturing operations for chips and circuits, and eventually all competitors have to go to them.
Inspired by past successful examples ...
Twitch is Youtube for gaming. PlayFab makes indy game payment easier. Square took Visa/Master's business for people on the go. Basically, take someone's existing business and make it. For example, Starbucks took Maxwell House's business, Amazon took Barne's and Nobles business. Or you can offer a second, better operations for a new startup business and offer competition.
How the model works
Sell your business back to the business competitor so they could kill it :-)
How does become ecosystem?
Everyone will like you, just not the big competitor. But that is OK.
How you can copy/expand it
Barrier for competitors
No barrier, but who needs it.
Expansion or exit strategy
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