Let's make it a little easier by talking about a slow code project instead of a movement. I think that could look something like Jon Blow's development of the Jai programming language, which is in closed beta after being developed for several years already. He's emphasizing the joy of programming.

He also has millions of dollars, thus, years to devote.

We might exploit this example to say about a slow code movement "people in the slow code movement would recognize at the start of a slow code project that they will be working in relative secrecy for several years".