Apps from Apple have exactly one function: They help sell Macs. They serve no other purpose which is why, concurrent with the release of OS 10.9 Mavericks in 2013, most of them became free.

The difference between the free (GarageBand, Pages etc.) and the paid ones in the Pro Apps bundle (Logic, Final Cut etc.) is that the Pro Apps have phone support. Apple does not advertise this but it's true. A couple of years ago, someone decided to make this exclusive to the Education Store—quickly, orders came from the top to, again, let anybody buy it—because THEY HELP SELL MACS!
Apple Pro Apps Bundle

Back to BIAB for the Mac. There are windows that look like System 7 or earlier and a few interface bugs here and there because of this. So, yea, yea, yea, it could use a ground up rewrite but, once you get used to it, the workarounds become second nature and I think, "Wait till next year…"

BIAB 2024 Audiophile, 24Core/60CoreGPU Core M2 MacStudioUltra/8TB/192GB Sequoia, M1 MBAir, 2012 MBP/color]
[color=#FF0040]Digital Performer11, LogicPro
Finale27/Dorico/Encore/SmartScorePro64/Notion6 /Overture5