I was inspired by the AOSA many years ago and I had studied (and held out) as an example the Apache architecture (about 18-20 years ago). It is indeed a pity that so many younger software engineers really have no idea of how heavily used real-world systems get built. Nor do they understand all the various tradeoffs and corner cases that need to get handled to make products work well in real life.
Building Apache from source (including a few key addon modules) and configuring it to work for a small set of tests was step 1 at my organization then. Those successful at this would then get into the source itself. Fun times!