The reality is that reliable backports of security fixes is expensive (partly because backports are hard in general). The older a distribution version is, generally the more work is required. To generalize somewhat, this work does not get done for free; someone has to pay for it.
People using Linux distributions have for years been in the fortunate position that companies with money were willing to fund a lot of painstaking work and then make the result available for free. One of the artifacts of this was free distributions with long support periods. My view is that this supply of corporate money is in the process of drying up, and with it will go that free long term support. This won’t be a pleasant process.
And that skeleton of a system becomes easier to test.
I don’t need to test ~80 - 100 different in-house applications on whatever many different versions of java, python, .net and so on.
I rather end up with 12 different classes of systems. My integration tests on a buildserver can check these thoroughly every night against multiple versions of the OS. And if the integration tests are green, I can be 95 - 99% sure things will work right. The dev and testing environments will figure out the rest if something wonky is going on with docker and new kernels.