In general, tech is an industry with high fixed costs and low costs per unit sold. That kind of pricing structure tends to limit competition.

Nvidia was founded at a time when outsourcing chip fabrication was common and viable, so all Nvidia had to do was focus on design. After a series of failures and near bankruptcy, Nvidia was finally able to invent the idea of a GPU and sell it to the marketplace.

After that Nvidia bought several companies to round out its patent portfolio and capabilities, remaining a dominant company in an industry it created. The only real competition was with other companies that had previous chip design experience.