Hundreds? I think you mean tens of thousands. Microsoft products are expensive and their costs are embedded in everything.

Need a replacement workstation? Add an extra hundred for the unavoidable cost of Windows.
Office and Teams are an ongoing subscription fee that costs about $100 per employee. Sharepoint licenses run over a thousand a year before you add in custom modules.
Microsoft's Azure cloud host is now running most things like your company's exchange server - so you pay for the Exchange service subscription AND the hosting costs.

The list goes on.