[cognitiveosman]

Really nice dimension you highlighted - It is indeed many legacy systems are running business critical application which are quite expensive to replace, we see that in the finance, insurance, banking, and aviation domain. On important dimension to consider when learning technologies is to always invest on learning the fundamentals which rarely change with time. For example, investing on developing sound understanding of TCP/IP protocol will be helpful regardless of what technology vendor you will use and the basics remain (almost timeless)