Likely because DNS worked just fine without EDNS client IP (and indeed DNS) for decades. For example, I remember the use of the 4.2.2.2 server, which was globally accessible but US-based. The responses though were 100% usable wherever you were on the planet. Equally, a national ISP running DNS servers would get you a country at most; a /24 gives you city or better location, carrier-grade NAT aside. Latency between the client and server may be slightly higher, but that's the end user's problem and not an issue for the site. In any case, it sounds like the Cloudflare source IPs for recursive DNS lookups are locatable via GeoIP, so I fail to see the problem.