a) Atrophic to one's career
b) Just a generally miserable way to live as a programmer
I don't believe things are so bleak, and I think people would benefit from being open to that possibility.
Career growth after entry level rarely hinges on acquisition of technical knowledge. If anything, technical knowledge is the easiest to acquire which is why entry levels can claim it without much work experience. Organizational navigation, team work, delivering actual results, knowing how and when to apply those skills (and when not to) mostly come with experience, and those are going to be the determining factors for promotions beyond entry levels.
> b) Just a generally miserable way to live as a programmer
I would argue it is more miserable to not have developed those tacit skills so that keeping up with the latest and greatest is the only element of competitive advantage to stay relevant. I would also speculate this might be the reason why juniors tend to over-emphasize the latest tech as the greatest tech, because they don't think they have anything else to be competitive in the job market.
Curiosity is not an algorithmic virtue, it doesn't apply to every case. It needs to be tempered with a dose of conservatism to deliver results in real world.
As Alan Kay perfectly puts it, fashion driven industry, and naturally one must keep themselves fashionable.
So up one goes rewriting that working WCF service into gRPC, because fashion.
But is ok, after all someone needs to pay those consulting rates and keep projects rolling, book industry happy with introduction and best practices books, and new themes for conferences, and most importantly blog posts with postmortems regarding technology migrations.