A subtle shift that comes early in the PHB is nudging the player away from the perceived need to have 18 in stats.
D&D stats classically range from 3 to 18, based on the original character generation of “roll 3d6.” Higher numbers are better. Under the original scheme of rolling three six-sided dice and taking what you got, only 1 in 36 characters got an 18, and characters were as likely to be below-average as above-average. When you take The Hobbit as your example of what D&D should be, playing as a below-average character might sound like a fun roleplaying opportunity. You got more challenge because you originally did not even arrange them, so if you rolled a 10 Strength, you either were not a Fighter or were not a very strong one.
Most people wanted more power and the feeling of being the epic hero, Legolas not Pippin. Others saw the inherent imbalance in a game where one person’s stat modifiers could total +20 while another got -2 (although you will again find advocates for imbalanced play). Alternate methods of rolling characters were developed, notably limitations on randomization through rolling more dice (4d6 & drop lowest, 18d6 and assign as you like) or eliminating it through a fixed point buy system.
My brothers who played decades ago seemed offended by “kids these days.”
In 3rd Edition, you wanted at least an 18 in your primary stat. All optimization assumed that because so very much was dependent on your primary stat. Builds relying on multiple stats fell behind on the power curve because +4 to a stat meant +10% on a d20, and 10% better at almost everything that matters adds up quickly.
5th Edition tones it down. The standard stat array gives you a 15 as your best stat. The point buy method does not give you an option for an 18 or enough points if there were one. At least as critically, the stat increases you get as you level never let you push a stat above 20. This is the EVE Online effect of capping low: your 18 grows to 20 and stops, so you must invest the rest of your stat growth horizontally. Compare with an optimized 3.5E character that might have started with 20 in its main stat.
I think that restores a bit of sanity, but it might be difficult to re-train players after a decade and more in the opposite direction.