I'm tired of typing so I'll just quote some people that said it nicely.

We had this issue in Beta ARR. Yoshi said he would no longer allow the team to create content like this for expansions in the future because he understood the servers couldn't handle it. Thus why HW had much less of these at the start.
They know what they presale. They know what how hard they advertise. They know how much money they're spending on Twitch streamers to advertise the game. They know how many subscriptions they have. They know what their servers can handle and how much.
By placing TWO bottlenecks extremely early in the MSQ?
By having both RDM/SAM, the brand new classes, use the same resources as the MSQ bottleneck?
Yeah, this couldn't have possibly been predicted /s
Here's the thing that people forget when I see posts like this. This is an exact repeat of ARR launch and on top of that they knew how many sales they had and pre order codes entered. They had all the data they needed but made a conscience decision to not adjust and "keep trying." There really is no excuse trying to justify this.