You do realise that Linux get update[sic] often as well?
Depends what you mean by 'update'.
Linux gets frequent updates to fix bugs. It also gets infrequent upgrades, which add new features and which change the way the system functions.
Updates need to be frequent, or at least as frequent as the emergence of the bugs they fix, whereas upgrades need to be infrequent to allow time for testing before production deployment.
A six-month update cycle is too long to wait for fixes whilst a six-month upgrade cycle is too short for adequate testing of production systems.