The Perfect Storm is a movie about the confluence of three weather events that combined to create a situation the resulted in the loss of all life on a fishing boat. It's a good movie, and certainly one that might make anyone think twice about sailing off into the North Atlantic in bad weather. I certainly wouldn't want to be traveling on the water when any type of hurricane might present.
Glen Berry writes about a perfect storm of a different sort. The perfect storm to upgrade, with the confluence of three events he sees taking place soon. We have quite a few performance related changes coming in Windows 2019 Server, in CPU hardware, and storage technology. Those three changes could dramatically improve the performance you might see from your SQL Server licenses.
If you were planning on updating a legacy system with a new version of SQL Server, you might do well to consider some of these hardware and software improvements. I don't know what the costs might be, but that's certainly something you will have to consider for your environment. The argument likely would be that if you're updating the database server, why skimp? This is a limited resource and one that can affect your entire system. Spending some money here might make a significant difference to the way in which your system performs.
This might be a perfect storm of a different sort for your budget and your accounting department as upgrades for SQL Server are likely to be pricey. The improvements could dramatically improve workloads by lowering the time users spend waiting or increasing the throughput of queries. Those might negate the cost of any hardware and software costs involved since time is a valuable resource and saving time is worth something.
The problem for many people is that if you aren't writing good code, then you might not get the benefits you want from the upgrade. Certainly the performance improvements might be lost under poor query performance. Upgrade to take advantage of improvements if they are something you need, but please, learn to write better code, and ensure your developers are regularly looking for better ways to use your expensive SQL Server licenses by writing more efficient code.