4-man variants for endgame content going forward?

[Reinha]

Tell me how this isn't gatekeeping content behind the idea that it should be reserved for only those who are willing to invest even more time outside of the actual content?

Why can't we just learn the content, jump into a group and do our thing?

8 man content is not gatekept behind having a fixed group like PotD and HoH are, for example. We are perfectly capable of making a PF group for any raid. Completing it is another matter.