You're thinking as if it was Windows. In enterprise environments, companies control a set of proxy repositories and whitelist/blacklist packages.
If you're a dev and need a specific package (or set of packages) that aren't listed, then you can request it through a ticket.
What do companies gain from a full Linux environment?
Better integration with services (if it's already a linux/unix shop).
Cost reduction from licenses (although an increase in training/in-house expertise costs)
Machines will run supported as long as the silicon stays welded.
Better security if implemented right.
(A big issue of Windows is that for running secure you need to cut a lot of it, which generates shadow IT).
However if not done right, there's a long list of head-aches, including some software that's no longer compatible and has no real professional linux option (design suites, SCADA/ICS, CAD software, etc).
Even if there's a similar tool, it's highly possible that there are trade-offs that will require a lot of investment.
In most cases this gets solved in two ways:
Designers get a Mac so they can stop whinning and IT churns a solution to integrate all the outdated stuff running on that OS with the rest of enterprise services.
Windows stuff that doesn't require a beffy computer gets deployed on a VM with RBAC integrated with the company's IDP.