Nothing to buy or sell. You can have perks/rewards like merch or even devices with the OS installed but it still isn't a purchase.
There are a number open source projects that have crowdfunded successfully.
Discussion
Still, it doesn't help them in rivaling Microsoft, Apple or Google. These companies have the advantage of building the best products because they have so much money.
Linux on laptops cant compete with Windows or MacOS in terms of UX, features and the ecosystem of apps. FOSS scales to only a certain degree. We need bigger and better open source projects.
One such project is DeFiLlama, an open source project that rivals VC funds projects in data dashboards. Have you checked it out?