What I meant was that they only went back and added this part to the story because they saw how popular he was and that a show around him would draw money.
Maybe not technically a retcon but certainly in the spirit of the poster who I responded to's point
This is accurate. Furthermore even during the pre-Disney+ era, it was unclear if Agents of Shield was MCU canon or not. While the Season 1/2 hydra reveal and storyline was GENIOUSLY done and did an extremely memorable and well done integration between TV and film (Captain America: The Winter Solider), that was pretty much the end of it. They fetched the Helicarrier that Fury showed up with in Age of Ultron, and that was the last real time they played a role, and the MCU films never highlighted Coulson again until Captain Marvel.
This reason for this? Joss Whedon said at the time, on the record, in his mind and creative intent for his MCU works, Coulson was still dead. That kind of broke the unspoken code of Marvel to play it cagey to keep people watching, but Joss wasn't going to pay a lick of attention to the AoS. It would be up to them to make themselves compatible with his film vision. This despite the fact he helped create the series, directed the first episode, and his brother was the showrunner. Yeah, it doesn't make any sense.He was the guy who, inc reating AoS, brought coulson back, and then turned around and said in so many words "not my sandbox, not my concern".
Shit like this wouldn't go down now because that all was before Kevin Feige basically became the Rick Berman of the MCU. Which is something I think needs to be said a lot more by the way. Rick Berman (and his team), for his many faults and failings, was doing a very consistent TV-Film cinematic universe 15+ years before the MCU. The rules and practices he built around Star Trek's fictional universe, which did not exist before he took over, created much of Trek as we know it. Something like the Agents of Shield/Coulson situation. would never be a question to canonicity or consitency under him, and now, under Kevin Feige.
Slight aside, this is why I like Alex Kurtzman as Head of Trek now, despite my gripes with some of his creative choices. Multimedia fictional universes need a Master Chef overseeing the kitchen. Trek has Kurtzman, MCU has Feige. Star Wars has Filoni and Favreau (and seriously, consider what a mess Star Wars was in the inept hands of JJ Abrams saying fuck-all to the rules of the fictional universe). Franchises are generally just better for it. As David Blass said on twitter, he told his production staff to approach Picard as a period piece about the future, which means implimenting previous styles and concepts and looks, not putting a personal spin on it. The name of the game is that that kind of top-level consistency makes these fictional universes not haphazard.
It's absence gets you, well, Picard Season 1, Discovery Season 1, the Star Wars Sequels, and the Agents of Shield situation (and I liked AoS!).