Devices with official LineageOS support will get OTA updates. Newer devices with A/B partitions will even get seamless updates like stock, where the update is applied in the background and the user just needs to reboot to use the new version.
Again, ignore the fact that iPhone is closed source, it does provide a infinite software update until it's broken, which is better service than most Android phone, even if considering installing ROM.
That's a big thing to ignore.
> it does provide a infinite software update until it's broken
No, it provides a long (several year) life cycle, but Apple does EOL devices.
> which is better service than most Android phone
Absolutely agreed.
> even if considering installing ROM.
Less obvious; Apple probably beats many aftermarket ROMs on lifespan (while losing on other points), but it's a lot closer competition.
P.S. If/When they do and you use LOS be sure to tip LOS and the developer ;)