I've torn out several Asterisk systems because that random local dude grew tired of dealing with Asterisk. Toshiba, which is a competitor of Avaya, does get close to that.
I'm absolutely positive Asterisk is better than Toshiba in that regard. I've invented some absolutely hideous hacks to get Toshiba systems do complicated call flow. But for a minuscule office with less than 8 phones, say a chiropractor or hand made guitar manufacturer, Toshiba does the basics, does it well, and is much easier to install. The systems don't do much, but they do it well. The pbx can hang in a damp and dirty location for years and still work. Internet service here is too unreliable to have a hosting solution or sip trunks, unless you want to pay AT&T thousands a month. The wiring can be 50 year old 25 pair, and the phones work fine. Businesses don't want to switch to ip phones since they don't have the cabling infrastructure for it.
Asterisk is completely scriptable. Somehow I doubt that Toshiba system can do what we've needed done with respect to different stations ringing at different times of day, complicated dialing permissions, logging Charter Business outages, recording customer service interactions, etc. Each of those things required a small amount of labor, and no equipment purchases.
Of course our dude might leave the industry someday. Then we might have to hire a different dude.
I'm absolutely positive Asterisk is better than Toshiba in that regard. I've invented some absolutely hideous hacks to get Toshiba systems do complicated call flow. But for a minuscule office with less than 8 phones, say a chiropractor or hand made guitar manufacturer, Toshiba does the basics, does it well, and is much easier to install. The systems don't do much, but they do it well. The pbx can hang in a damp and dirty location for years and still work. Internet service here is too unreliable to have a hosting solution or sip trunks, unless you want to pay AT&T thousands a month. The wiring can be 50 year old 25 pair, and the phones work fine. Businesses don't want to switch to ip phones since they don't have the cabling infrastructure for it.