One of the points that has remained consistant between all editions of D&D was that older mechanical material was no longer just "drop in" to use. You could convert it, but it wasn't RAW to use.
And that's the point we are disucssing here. Is this a continuation, where we can continue to use all of the previous material? Is it a continuation where a large amount of the material has been replaced but we can continue to use the rest? Or is it a "continuation" where some/all unaddressed mechanical material doesn't continue forward? Because the last doesn't fit the definition of a continuation.
That's not correct.
I went through this previously in the thread, but this whole edition mess started with the very first changeover. With the second edition- the one that explicitly was backwards compatible with the first edition, and allowed people to continue to use all of the old stuff (especially the modules and adventures) as mix-n-match.
Zeb Cook has talked about how a lot of the changes they wanted for 2e, like ascending AC, were nixed for that very reason.