I thought the writer Neal Stephenson did an excellent job of explaining the phenomenon of lock-in with regards to rocket technology in this article: http://www.slate.com/id/2283469/pagenum/all. It is an excellent reminder that the technologies we have are often the result of contingent (historical) factors rather than rational ones.
There's another great example here, by Alexis Madrigal. Apparently, the U.S. Navy ended up deciding that light-water reactors would be THE model for nuclear power. Another one about electric cars and electric refrigerators. And one more about, of all things, pants.
Here are two examples of lock-in that are near and dear to my heart -- that is, they drive me crazy:
1. Have you ever wondered why the U.S. math curriculum goes Algebra 1, Geometry, Algebra 2? It's a completely irrational system that no sane person would design. Algebra 2 classes start off with an extensive review of algebra since it's been 15 months since the students last saw algebra. In fact, the review can last nearly a quarter of the year. Perhaps the review period would last only a few weeks if the students were to go directly from Algebra 1 to Algebra 2. What's worse, many students aren't really developmentally ready for Algebra 1 when they take it; many need a more robust pre-algebra course. A more rational sequence would be Geometry/Pre-Algebra, Algebra 1, Algebra 2. Geometry is developmentally appropriate in 8th grade and serves as a perfect medium for pre-algebra concepts: that x stands for something that is unknown but fixed, and that one can use geometric properties to deduce x, makes sense in a geometric context. One can even get at the idea of x as a variable with similarity and ratios. And yet, year after year, school district after school district decides to keep the irrational sequence unchanged.
Why? At around the turn of the last century, when high schools were the new thing, students took Algebra and Geometry. Period. Geometry, with its logical proofs, was deemed material for seniors. As time went on, more classes were added on, always at the end. First, Algebra 2/Trigonometry was added. Then, Pre-Calculus was the senior math class. Now it's Calculus -- and thus, Algebra 1 got pushed down to 8th grade.
2. You know I'm going to talk about debate tab. I have never tabbed a tournament on notecards, but I know exactly how to do it because I've used the current generation of debate tab programs. The programs are electronic notecards. Don't get me wrong -- I'm very glad that we have the programs! They automate the mindless tasks and don't make careless mistakes like people do. My point is that when the tab programs came along, they were designed to do the existing tournament practices, only more efficiently. The debate community hasn't seriously thought about whether we can design better practices that can only be done by computers. In other words, we are locked-in to tournament procedures (brackets, speaker points, dropped high-low speaker points) that were designed to be (relatively) easy to do by hand, even though we have phenomenally powerful optimizing devices at our fingertips.
A high-low pairing algorithm literally ranks all the teams and then pairs them off two-by-two. Why not have a computer run 10,000 possible pairings and pick the best one?
I've written another post about lock-in.