Not everyone can afford it. 🤷
Discussion
A lot more people than you imagine can afford it but have other priorities
Bro I get my Pixels on eBay from reputable sellers who make sure the bootloader is unlockable and I never paid more than $200
Since GrapheneOS's update cycle is only reliable for a few years at a time, it makes zero sense to buy the $900 Pixels that are brand new. So I only buy the cheap ones from years ago. Easy peasy. They last me quite a few years. I'm on a 6 Pro, and my home phone which never goes anywhere is a 4a
Thank you! I'll look into it. I saw one new for €1200 ( ~$1400) and I dropped it.
You can do it 
😂 There's only one way to find out.
Yep! So I did a search and since I don't know what country you're in, searched for Pixels at eBay which is where I always go.
You want to make sure go to the sellers pages to see what else they offer. It's a good bet if they have a good rating and just only sell phones & phone accessories (not like, an assortment of crap as it they're cleaning out their attic) and if you find a phone you like, go to the item and click "Message seller" you need to ask them if the bootloader is unlocked - if the listing contains the word, "Unlocked" that is not enough to know, because usually that refers to whether the phone is locked in with a certain wireless carrier, not whether you can flash the ROM. So always ask if it's not clear. The full description (scroll, scroll) may also say "oem unlocked" or "bootloader unlocked". That's about all you need. Then go to Graphene web installer and it will do the rest if you connect your PC to the phone via USB.
Here's an example listing: https://www.ebay.co.uk/sch/i.html?_dkr=1&iconV2Request=true&_blrs=recall_filtering&_ssn=reboot_hive&_oac=1&_nkw=pixel
The 4a was my favorite. Small and a headphone jack
Anker has these adapters that fit in the usb-c charging port and connect to the 3.5mm male end of your wired earbuds or headphones. I have one and it works great. No sound quality issues, and it stays in pretty well https://www.amazon.com/gp/aw/d/B08Z3B5QL3
I use Swappa for the same reason.
Still have to ask the seller about the bootloader before buying
They have good filtering