I understand the distributions generated by those 2 methods and yet your example and assumptions for it are so far off from how the game is actually played that the criticism is next to worthless. By the time you can do 4d10 damage in a single attack or do 4 different 1d10 attacks you will be fighting enemies that can easily take the 4d10 hit and still live. After that point is reached neither distributions is really better or worse.
Let me explain: When people provide examples, they're often ILLUSTRATIVE of a point. They're not intended to be simulations.
They were meant to convey an understanding (which you indicated was successful in the first two words of your statement), not to say that you'll encounter that exact situation. However, the same phenomena happens between rogues (one big sneak attack) and monks (3 or 4 attacks, but smaller damage per attack), and in countless other areas.
DPR, in general, is horribly oversimplified in isolation, but people cling to it because it allows them to exercise their junior high math skills and sound oh so smurt (Look! numbers and percentages! And the numbers and percentages both have decimal points in them! I even put 3 or 4 numbers to the right of the decimal!). Don't get me wrong - as an academic exercise, it can be fun to figure out - little puzzles can be neat - but it has no place at the game table, and doesn't really address the efficacy of the different classes correctly. It does, however, result in people making silly arguments about things being too OP, or things being 'horrible', because the DPR doesn't match up to the DPR of another build - despite the balancing factors that are not directly tied to DPR.
There are enough variables in the equation that the only reasonable calculation of whether a class is good or not is: Play it for a few months. If fun, it is good. If not, then it was not a good fit for you, but might still be good for others.
Using that measuring stick, I've played barbarians, bards, clerics, druids, fighters, monks, paladins, rangers, rogues, sorcerers, warlocks and wizards in 5E. I've played them in multi-classes and pure builds. I've played them at high levels, and low levels. I've played most of them in campaigns, all of them in multi-session adventures, and all of them in one shots. I've sampled the artificer, too, and although I have few fears about it, I have not played enough of it to include in my comments. However, for all these other classes, while there are few subclasses that are less fun for me, and a few subclasses with mechanics that do not work as I think they were intended, EVERY class (and every race for that matter) passes the mark of being FUN and EFFICIENT. Further, I've built PCs that the DM considered to be either overpowered, or just more efficient than most PCs, in EVERY class. Some were damage machines, some took all of the DMs toys away from them, some made the party near invincible, others controlled the social and exploration pillars to the extent they made it hard for the DM to entertain us without us breezing through the challenges.
You can calculate DPR all you want - but you need to recognize it is not significant evidence of a class being good, bad, broken, underpowered or anything else. It is one tiny element to consider, but only 3.06748 to 5.23642% (see how SMURT I am) of the total equation and can downright LIE TO YOU about how effective a PC is if given too much weight - which it almost always is by the people that raise it.