Are integrated amps technically better than separates?

I'm assuming we are talking same class of amplifier and the integrated has the features you want. I'm thinking the integrated could actually be an improvement over separates due to being a more "direct" connection. Taking away the flexibility factor of separates, is my line of thinking correct?
This is the first post I have ever made on Audiogon, and I am not a tweaker whatsoever (I just changed speakers after 25 years when a great deal for KEFs became available). I look long term and buy used or new depending on the item. I have found the most difference in the phono section by far (arm, cartridge/phono stage and table in that order). I didn't realize how much improvement could be gotten from a separate phono stage (or head amp as we used to call them). 

My integrated amp which is phenomenal (Plinius 8200MKII), has a built in phono stage which I thought was equal to the other parts, and until I got a MC cartridge (VanDenHul Special One) I never thought about it. When I got back into thinking about the hardware in the past year or so, after upgrading my Rega P5's arm to the one on the new P8 (the dealer sucked me down a rabbit hole) and finally upgrading the table itself, someone mentioned that although the Plinius phono section is good, I could get a big improvement with relatively few dollars spent (although relatively is a relative term). 

Since I upgraded each part in incremental steps, the arm improvement blew me away, and although the table sounded better it was a very subtle improvement thought it has a couple nice features. I just got a Sutherland Insight phono stage a few weeks ago (lucky to find one used) and once again I was blown away. It was based on the recommendation of several dealers. I would have bought a new one if I didn't find the used one. The guy who sold it to me set it up for me based on the VHD specs. You can see I am not a tweaker.

Bottom line in this discussion, make sure to separate the phono stage first, then worry about the integrated/separates argument. I lean towards integrated for space and value, but like I said, I am not a tweaker or tube guy. For the hardware hobbyist - have fun with tubes, separates, mono blocks, sub woofers, etc. For music lovers who like to keep it simple and mostly listen to music while doing other things KISS.
I would like to know why an integrated needs a separate power supply for the preamp and amp sections. My DAC puts out 4.2 v balanced which is more than enough to run an amp to full power. The pre and first stage amp sections are running at the same voltages. Isn’t my integrated pre section pretty much acting as a selector and volume control then?  I am using a Pass Int 250 which supposedly has a minimal preamp internally.
Enlighten me

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I believe either topology can be as good as the other, it's just down to the price you want to pay for the functionality you need... personally I prefer separates. My preamp has inputs for MC (transformer) and MM cartridges, four other analogue inputs, a 64dB attenuator with 128 steps and four individually powered stereo pair outputs. That gives me the functionality I want with little compromise to quality. Actually, I think the volume control is a weak point in many amplifiers and a well implemented stepped attenuator can make a real difference on its own.

Would you fill in some of the details of what you know about power cords?  You've told us that a power cord that's not up to the job is going to hurt the sound, but what are the basic requirements for an adequate power cord?  One that will not degrade the sound in a system the average 'Goner might own.  

What impedance is adequate?  Should it be solid or stranded wire?  What gauge should it be?  What about dielectric materials?  As your system becomes more sophisticated, do you need a power cord to do more that deliver electricity?

I would greatly appreciate it if you can give us any guidelines or refer to where we can find answers to these questions.  This is one of the more confusing topics in audio for me, and one that seems to cause the most heated arguments.