I’m not saying you can’t get something better or less expensive, or both, but I still consider $20 to be ‘reasonable’. The chargers in your first post linked to there are in the same region ($13-$25). I’m not including promotional deals, because the skews like-for-like comparisons, there’s nothing to say the new Apple charger won’t be available with a coupon from somewhere online.
Also, you can look at it another way: you’re no longer getting a less-than-best charger in the box, so you can buy the charger you really want instead. If you can get a great one for $10, I don’t see it as a big deal. And, honestly, I don’t know anyone who doesn’t already have a charger or three.
(As for the EarPods, those were always a waste – I have brand new ones sitting in drawers, as they don’t fit my ears.)
Addendum: Also, a lot of companies don’t make well designed chargers for different plug styles. For instance, the UK version of the Aukey charger in your post is an ugly chunky thing that is bulky, compared to a nice Apple design that has folding prongs. The Aukey one is only £2 less expensive. I honestly think Apple’s charger price is now more in line with the market.