I worked at Microsoft.
Windows releases, Office releases, Visual Studio releases.
I started my career in the mobile (originally Windows CE) compiler team. Releases were a big deal, support contracted lasted seemingly forever. (Ironically, internally the mobile compiler team was actually very agile, with weekly full test passes happening, the compiler always being in a shippable state, and development occurring in what would now be considered modern practices.)
Microsoft was getting destroyed because they were very non-agile. As soon as the iPhone came out, Apple started releasing a new OS every year, and back then OS updates had significant developer API improvements. Windows Phone couldn't complete with that. I remember how lacking the camera API was soon as instagram types apps with filters came along, Windows Phone went from amazing to instantly behind the curve.
Look at what happened to Hotmail when GMail came out, it took Microsoft years to catch up just with the storage space increases, UI improvements took even longer. Microsoft ended up losing their top spot in the webmail game.
Internet Explorer (eventually Edge) was tied to OS releases. Even when MS started to invest in their browser again, being tied to OS releases meant it could never complete with Chrome releases happening every few months. Edge would have a big release, pull ahead on benchmarks, then 6 months later be out of date and behind the curve again.
Agile forces code to always be in a shippable state, which is a good thing. It doesn't let code become bug ridden and then say "we'll fix it sometime later".
That forcing function alone is a huge improvement.
