Why am I never offered an update to Version 1809?

Hi, question is repeatedly asked.
1. MS is coy about delivering it via WU - slowly being released.
2. MS imposes some restrictions - particular issues- see thread on re-released 1809 in News
3. You can override those restrictions by upgrading manually- download an iso.

I prefer the latter course anyway- can update my disk images before upgrading.

Note: you have Pro - do you have feature upgrades deferred?

Some would say be thankful,
I had upgraded way back when the update was first released, had issues, and rolled back. Then just sat back and waited to see if it would auto update again on its own.
Was beginning to think it wouldn't because I had done the rollback. It only just updated on its own last week. I hadn't even done a manual check for updates. I just got the prompt to reboot to finish up the update.
I have no idea what triggered it?

Once you have done the upgrade, then use the fact you have Pro and defer feature updates for 365 days. as @alphanumeric says, 'some would be grateful' - receiving feature updates on first release can be a bad idea- best wait until after the first subsequent major update.

And then create a new base disk image (assuming you know how valuable disk imaging can be and use it- e.g. Macrium Reflect -free + external storage for images)