That’s a rather bold statement to make, especially considering I have headed one of those large-scale deployments. IBM has over 100,000 Macs, up 50% from their previous deployment goal. There are plenty of Mac deployments in the 4 and 5 digit range. I work on several a year!
Specialist industries have the most trouble switching, but legacy apps are less of a problem these days. Most are either a web app already or slated to become one, largely because mobile has made cross-compatibility a requirement. Things like CAD are the exception because they need native clients and aren’t mobile centric.
Backend changes usually aren’t the bottleneck for cross-compatibility, if their app was written with decoupling in mind (thank you Agile). Throw that out the window if it’s some ancient SOAP monolith. They have bigger problems than their choice of user OS.
Assuming your instance name implies you are in the EU, things are just different for IT over there. The cost savings from adopting Macs can’t materialize given the conditions.
It’s not for every org or team. I often work with small IT teams to provide the expertise until they are able to gain the institutional knowledge themselves. It’s usually a slow process, with transitions on the scale of years for the large companies.