It's not a joke, it's intended to convey the wisdom of not thinking "the next big thing" will solve all your problems, it is intended to focus on the importance

It's not a joke, it's intended to convey the wisdom of not thinking "the next big thing" will solve all your problems, it is intended to focus on the importance of fundamentals, and of relying on using engineering skill to solve problems rather than fancy gadgets, it is to point out the value of developing technical acumen rather than becoming a tool bound technician. If you define yourself by the technology you work with you aren't an engineer you're a technician.