I see two factors why every cURL release is more popular than Linux releases:

a) Most people get their Linux fix through distributions, nobody [1] is compiling their own kernel any more. So knowing about a Linux release is mostly for curiosity sake, what can be used in x months/years.

b) cURL is also extremely widely used [2], so every release matters and can easily compiled/installed directly, without waiting for distributions to catch on.

[1] exceptions prove the rule

[2] even Microsoft added an 'curl' alias for accessing URLs via HTTP in their PowerShell