Also, FWIW, when I need to run Ignition on my Mac I just use the zip distributions. They can be started/stopped by ignition.sh start or ignition.sh stop, and I think because I have Terminal.app set up as a developer tool in the security settings I never have any issues running it.
Small locations. Usually have a Mac Mini as a shelf spare. Plus only recently built out a dedicated IT team. Gave more peace of mind from a security standpoint when dealing with limited resources to monitor hardware. Windows drives me crazy and not quite comfortable enough with Linux to not waste many hours when having to maintain an asset.
Apple places extra roadblocks in the way of software distribution. Presumably to protect their userbase (from themselves), but, in my opinion, more to protect their walled garden. Regardless of justification, it is a roadblock that will cause multi-platform products to lag on Macs. Unless you are willing to work around the restrictions (aka "hack").
I think your criticism of IA is unjust--you should be complaining to Apple.
I just merged in the work to notarize the Ignition Installer and it should be available in the nightly and the next release (8.1.31).
But ill throw my two cents in here for some context:
Notarization of a product as complex as Ignition is not trivial. Signing Mach-O execs from the deepest part of Ignition outwards while maintaining hashes/signatures where Ignition requires it in a sane way during a build which happens many times a day without interrupting active development is not something which can be completed without great care. It's obviously not impossible (since its complete now) but as Kevin mentioned had lower priority to other issues which affect a much broader collection of users. In an ideal world we would have the bandwidth to fix all bugs and add new features immediately, but unfortunately that isn't the case, especially when there is (an admittedly grotesque) workaround available for this issue. Especially since most mac users are mainly in it for the Designer and the Designer Launcher has been notarized for some time.
Hope that helps contextualize the delay in this, and I hope merging this improves your Ignition workflow
EDIT: Updated from 8.1.30 to 8.1.31 to account for the hotfix release