It’s not just limitations to how fast they can deliver the update, there’s also the fact that they want to do so in a controlled way. If they missed some problem in the extensive beta period, they want to be able to intervene to avoid all users facing the same problems at the same time.
As far as I can tell you can manually check for the update and download it, automatic updates happen gradually. I’ve read some users that encountered the problem that if you do it manually, some Zigbee apps are not always automatically updated to the required V5 compatible version yet. (Could be those users didn’t give Homey enough time to detect the new app though).
If that happens to you, you can install the “test” version of the app in question (which isn’t to say it is unstable, most were tested for months now). If you do not get that new app for Zigbee devices after the update is running for a while, the devices won’t work until you do.
Those that had the update pushed automatically also received the new version of the apps shortly thereafter. But do give Homey some time to find the new app version.