Eh, I don't know about that. WotC has had quite a bit of time to issue an errata if they felt this was not the way THEY thought the rules should work.
I disagree. All prior editions saw errata issued for many many years after the PHB came out. Errata tends too get issued on common topics early, and more obscure topics later. This is a more obscure topic, since it's not all that common that someone would care if it is a distinct turn or not. So I do not think the lack of errata indicates anything.
It is not like this is a feature of the rules that I uniquely discovered. It is well known that it works this way, though probably most DMs and players haven't picked up on it.
It's a rare topic, as you yourself just admitted. Most people have not picked up on it, hence a lack of errata is to be expected on this topic.
I've also seen a few CS responses confirming that it is the correct interpretation. It isn't like this is a case of a poorly worded rule that is ambiguous. RAW clearly works as stated.
I'd like to see those responses. I do not think RAW is clear on this topic, since it does not speak to whether or not the readied action should be considered a turn or not. It merely speaks to when they act, which is not necessarily the same as whether or not it is a turn for the purposes of other effects.
It just isn't a problem. In fact it solves a few kind of cheap tactics that PCs can use from time to time as well. Fighters are supposed to be sticky, but not infinitely so and if a bunch of monsters want to rush past one en-masse it should be possible to create that tactic.
Much like your opinion that 4e has no rounds, I feel this is position is a wild exaggeration. Fighters are not infinitely sticky with this tactic. There are already checks in place for this power. We can debate if it is more or less powerful than it should be, but it's not some UBER power that breaks everything and therefore we
need to turn to an obscure interpretation of the readied action rules to deal with it. That
might be the case, but it's not necessarily the case.