There is two flaws in your analysis.
4e never had playable orcs. They gave some bare bones stats (for "NPCs") in the back of the MM1, but I don't think they ever got a PC writeup. Further, the first attempt at 5e PC orcs had the infamous -2 Int to clearly discourage them from the otherwise similar half-orcs. It's not until the errata'd orc (in Eberron) that orc stats were finally balanced for playing, at that was only a half-dozen years ago.
Further, what lore? Both 4e and 5e imply half-orcs are children of frontier orc/human peaceful contact (rather than the violent background of before) but 5e orcs up to Tasha's were still thralls to Gruumsh and barely able to keep their evil in check (and half-orcs suffered the same curse, tempered by... their human blood!) The lore still placed them as the "more intelligent" orcs, and even the 4e writeup described how they were more "human looking" than regular orcs (the 10% passable rule lives on...). Further, 4e and 5e both talk about how half-orcs faced prejudice by those who hate orcs and have to work to get past it.
I checked the 2014 PHB, Heroes of the Forgotten Kingdoms, and PHB2 (4e). There is no great distinction in the lore other than "they are orcs made playable due to human blood".
So if you have some super-secret lore dump that clearly spells that half-orcs weren't just PC orcs prior to Tasha, I want citations.