@ronboco
You bring up a good point. A high end integrated can surpass mid-range separates, very true.
Each companies product lines are: Flagship = two box single function (like DAC, amp, or preamp), first level down… single box function, next level down… integrated of two functions… etc.
Why? Sharing space, power supplies, and functions compromises the performance. Also, upgrading… means the whole box when integrated… unless with swapable circuit boards (a huge sound compromise).
For folks that have limited funds (+95%) of audiophiles, every purchase is a compromise, with the expectation of an upgrade in the future. So, individual boxes at the highest level affordable is the way to go. Slowly and incrementally build a better system over time.
The big expensive integrated components are mostly for really well healed folks that want great sound and want it hidden and would never dedicate the thousands of hours over out lifetime an audiophile will to appreciate and assemble a system to cater to their desire for great sound.