There are. Several, in fact.

• Framework will sell you a laptop with no OS, but each laptop is certified 100% compatible with Linux
• For years, Dell has sold laptops with Linux pre-installed.
• StarLabs sells desktops and a couple different types of laptops with Linux installed.
• Lenovo (it may look like Windows only, but go into build one, and one of the OS choices is Ubuntu)
• system76
• HP Dev One (Hewlett-Packard)
• Purism
• and
• more

Hell, you can buy a laptop with Linux pre-installed from Amazon!

That's mostly focusing on just laptops; there's a dozen other companies selling desktop and mini-PCs with Linux, and some hardware manufacturers (Raspberry, ODroid?) don't even have Windows as an option.

There is a wide variety of laptops, desktops, mini-PCs, and SBCs to buy with Linux pre-installed. I'm more surprised that there's someone who thinks there isn't, than by how many options there are.