In my experience, it takes at least a couple of years to introduce a new technology to a large corporate (i.e. the ones that actually run enterprise apps).
Many large corporates will have multi-year enterprise licenses for things like IBM WebSphere. It might be years before they even consider a technology shift, let alone that shift becoming dominant.
The reasons are many and varied - resistance to change, need to prove the technology, integrating the technology with existing systems, changes required to methodology and process, instrumenting the new technology, vendor support, cost, skills availability, access to quality training, access to recognised certifications, tooling (dev/test/deploy), infrastructure, regulatory compliance... The list goes on and on.
Even when you take all of these... Nobody ever actually decommissions anything.
Cultural and methodology changes are massive in the enterprise space.