Treeanmmonk (your friend and mine) showed that there is remarkably little DPS drop off between the packet 5 warlock spellcasting and pact magic. But people whined they can't potentially cast six 5th level spells in a day and we're back to the pact.
What Treantmonk mostly showed is that he is a mediocre analyst who gets known by grinding and producing videos for beginners rather than for quality.
If you have ever tried to optimize for an MMO raid, a MOBA, or other sort of competitive gaming you know that both DPS and burst damage are important, with burst being frequently more important than DPS because the best control condition is dead and if you burst your target down to zero it doesn't have time to do things like heal.
A champion fighter is a DPR class. A wizard is a burst class, able to shut things down hard but with very low DPR (technically it's more hard cc burst rather than actual burst damage). And a warlock is a hybrid. They have two shots in their locker of burst, and then mediocre dpr that doesn't keep up with primary weapon users, partly due to fighting styles, partly due to feats, and partly due to magic weapons.
By removing Pact Magic and replacing it with generic cookie cutter half casting almost all the burst was removed from the warlock. No more Hunger of Hadar as a twisted fireball at level 5. No more Banishment for a looo g time. The warlock's burst was destroyed. The half-arsed half caster has all the burst of a ranger (or artificer).
With their burst destroyed the DPR needed to go significantly up to compensate. If the warlock only matched the ranger at casting then Eldritch Blast needed to be improved to match a ranger with archery fighting style, sharpshooter, and a magic bow (all while adventures are much more generous with bows than pact implements).
So after shredding the warlock's burst was the DPR increased to give the warlock a new role and rhythm? As you say Treantmonk showed that there was an actual drop off in DPR as well as the burst being destroyed.
And Treantmonk, being a thoroughly mediocre analyst, competent to run numbers but with no real depth to his understanding or ability to look at the whole picture then claimed that this was fine because he only looked at one piece of the puzzle. And others quote this as showing something other than the shortcomings of Treantmonk as an analyst.
Time and again I've seen reasonable ideas shot down because somebody looked at the PDF instead of, ya know, making a character and playing a minute with it.
And time and again I've seen bad ideas pumped up for the same reason and good things attacked for being different.