They stopped being thorough after John Siracusa stopped writing them.
Seriously, back in the days John Siracusa would dive into internal details. For example in 10.7 Lion (in 2011) Apple introduced full disk encryption. John didn't just stop at the usual description of the functionality, screenshots and performance metrics. He described Apple's then-new logical volume manager implementation to get this feature to work. He then speculated on Apple's future plans for the technology (pooled storage aka a single logical volume group spanning multiple physical drives) which became the reality in 2012 with Fusion Drive. This is the kind of review I wanted to read.
Seriously, back in the days John Siracusa would dive into internal details. For example in 10.7 Lion (in 2011) Apple introduced full disk encryption. John didn't just stop at the usual description of the functionality, screenshots and performance metrics. He described Apple's then-new logical volume manager implementation to get this feature to work. He then speculated on Apple's future plans for the technology (pooled storage aka a single logical volume group spanning multiple physical drives) which became the reality in 2012 with Fusion Drive. This is the kind of review I wanted to read.