This is the reality - most people won't spoof until they figure out it's the way to make a specific site work; and then they'll likely spoof for everything.
I'd also like to add that we forget that we're doing it, or at least I do. Once you set something up like that, there's never any reason to get rid of it; nobody is positively discriminating towards Linux.
I love when a ruleset (firewall, for example) has a "comments" field because I inevitably forget why I added something and then Chesterton's fence means I leave it forever, lest I spend hours a year later wondering why something broke.
Every time I try to change my user agent with a FF extension I get hit with brutal cloudflare captcha loops. How are you changing your user agent in a way that this is not a problem?