I bought a brand new one and it's fantastic. The used market for premium chairs in my remote part of the country is non-existent. I certainly would have bought a second hand one since they are so well built.
But even when bought new, something that gets used so much everyday is worth the price.
It probably won't fit the Shopify budget, it's super expensive. But having the same chair used in recording studios and is officially a work of art in the Museum of Modern Art [1] still makes me smile every day I go to sit down to work.
But I'd spent £300 on a chair before it that didn't last three months, wasn't as adjustable or comfortable, I couldn't get a refund on and for which there are no spares on eBay. 10 years in it's looking like a great buy.