Nice article, but from the viewpoint of an Ancient IBM Mainframer, I wonder how ANYONE can become really expert?? The mainframe ecosystem was created to solve o

Nice article, but from the viewpoint of an Ancient IBM Mainframer, I wonder how ANYONE can become really expert?? The mainframe ecosystem was created to solve one major problem - stability. Up to that time, upgrading one's computer system meant rewriting the application software - simply untenable for organizations with ever-growing libraries of critical applications. It also allowed the upgrading and addition of new software (application and operating system) and hardware with minimal impact on existing software. This relative stability allowed competent (but non-genius) folks to become real experts. When I see the current hurricane of ever-new and ever changing (evolving?!) software, the need to use an endless variety of differing products and technologies (including many libraries one has no control over), and endless discussions about the subtle differences and advantages and disadvantages of these competing / cooperating technologies.... How can anyone become really expert? How many can even become the fabled "full-stack" developer?? To me this really does not seem fair to the developer, especially those in smaller shops, where the developer almost seems to have to perform as a "full-stack" developer, whether they are or not. Just my 2 cents - I hope my impressions are wrong, but the app dev world sure seems scary!