Stripe is absolutely a tech company. They're a B2B SAAS company. They provide software that connects e-commerce platforms with actual payment processors.

Uber isn't at taxi company, since it doesn't own or operate taxis. Conceptually it's a platform for connecting independent taxi operators with customers, like Expedia or Craigslist or eBay.

Airbnb isn't a hotel company, since it doesn't own or operate hotels. Conceptually it's a platform for connecting independent hotel operators with customers, like Expedia or Craigslist or eBay.

SpaceX isn't a tech company any more than NASA is. They require science and technology but they sell rides on space ships that they own and operate.