The academic model is set up around scientific inquiry, in the Eric Drexler sense. That means that people are rewarded for moving information up The ladder of abstraction. The more general your theory or technique, the more you are praised.
In the Drexlerian sense, Engineering moves information down the ladder of abstraction. Moving down the ladder of abstraction clashes with academic incentives, leading to academic engineers creating proofs of concept for the sole purpose of validating general engineering principles or design concepts. The whole working system is left as an exercise to the reader. Proofs of concept, general principles, and designs are important! But they don’t push technology beyond TRL3 - Proof of Concept. Hence, The (idea) valley of death.
Because academic engineering focuses on the top of the ladder of abstraction, there are rarely feedback loops on the implementation of a design concept. A design can check all the boxes on a list of requirements (and hence be great for a paper) but completely fail to be a useful system. My quintessential example of this is how perfect right-angle corners at the bottom of a cut-out are completely free (and the default!) in a CAD model, but are extremely hard to machine correctly. These weirdly important implementation details are usually Tacit Knowledge which is why Prototyping needs manufacturing in the room.
Academia incentivizes novelty, not focus. Academic work is always judged by “what are the new ideas here?” Much more than “does it work?” In an ideal engineering situation, you would use as few new ideas as possible to get the system to work. This tension means that academic engineers will not work on some ideas or bolt on unnecessary fancy techniques because The word ‘novel’ is used as an idea bludgeon in academia. Bolting together a bunch of old ideas to get something work is great engineering practice, while it doesn’t create any general academic insight.
Academic culture prizes individual recognition via its use of citations as currency, etc. Many engineering projects require ‘teamwork’ in the sense of just doing the not-sexy work that needs to be done without remembering who did what. This isn’t to say that academics won’t do not-sexy work, but it does need to culminate in something paper worthy. There are an increasing number of academic papers with large numbers of authors, but as this articlenotes, there is a roughly constant amount of “esteem currency” per paper so the career capital per author decreases as the number of authors increase. Contrast to professional engineers, where reward is usually invariant to the number of people on the project and possibly tied to how successful it is, in which case the incentive is to have as many people working on it as necessary to make it work.
Academics want to do timeless work and engineered systems go obsolete!