According to the website linked earlier retail sales of RPGs increased by 40% from 2014 to 2015. That didn't just happen because 5e is a better made game than other games/editions. It happened because there are people playing RPGs now that didn't feel comfortable or welcome to do so before.
The books send a signal from the publisher as to:You're laying everything at the door of WoTC and 5e, instead of recognising that times have changed, the roleplaying community have evolved and nerd culture is at an all time high making it more socially acceptable...
The books don't play the role you think they do.
Who it thinks its audience is.
What sort of behaviour/outlook the publisher expects from players of the game.
What sort of behaviour/outlook the publisher expects from players of the game.
As I have already posted upthread, I don't think that 5e signals any rules change as to PC building.
But it does affirm that certain sorts of people are part of the gameworld, and in that way it sends a signal to the player-base about who they are, and what sorts of characters they might want to play.
But I think it's almost impossible, without access to the sort of information that only WotC would have, to know whether these signals significantly affect sales.