Are integrated amps technically better than separates?

Once you get past a certain level it becomes all about power supplies.  It's easier to fit over the top power supplies in separate components.

In a word: No

Like anything, specifics matter.

Could they be? Yes, certainly. The issues of DC coupling and impedance matching of each stage to the other vanish, not to mention the need for another set of interconnects, and the possible issues with proper connections at each of those points.

One of the other places where separate costs don’t really add up for the consumer is in the cost of the cases. Separates require more casework and associated assembly times, so you pay for that without any direct value add.

I am very happy to have turned into a Luxman integrated owner. It’s solved a number of issues with space and connectivity as well as improved the overall sound quality vs. the previous set up.

At the total price point I am at, I would have a very difficult time doing better with separates. Now, if I were to spend 4x as much with separates, that’s another story. :)

... and over the top power supplies wreak havoc on low level preamp signals and negate any benefit from "direct" connections’. One reason why most top-end preamps have separate power supplies.

One reason why most top-end preamps have separate power supplies.

Of course, nothing sells like excess.