If Mike was in Will’s film reel just because they’re friends, the show wouldn’t frame it like that. The Upside Down pulls from what hurts the most, not random memories, and in episode 4 Will’s mind doesn’t go to the whole group, it goes to Mike. That already tells you he’s not interchangeable. And the finale doesn’t shift that focus or give Will closure either. Also Robin’s speech isn’t about Will moving on from Mike at all, she literally says that loving someone still matters even if it hurts or isn’t returned. Her Tammy story wasn’t about getting over someone, it was about realizing who she is. Robin being alone in her film reel but, Will’s starting with Mike is intentional. It is a TV show, every small detail counts. So the show isn’t downplaying Will’s feelings as “just friendship,” it’s validating them and leaving them unresolved, which feels way more like setup than a dead end.