I think that when people say "why are other platform fighters so much like Smash", they aren't necessarily
wrong by definition, they're just looking in the wrong places - I think all the attention seems to be on two things:
- Knockback KO systems
- Melee tech specifically
Brawlhalla, MVS, Rivals 1, and NASB1; arguably the 4 most successful non-Smash platfighters in recent history (if you're talking "ever", then PSASBR probably edges out Rivals, and that will come back later) all play nothing like Smash beyond #1, and only half of them have #2 - but everything between those gameplay wise, except maybe the control scheme, are kinda abstract and tricky to comprehend - from a casual perspective, wavedashing is just "you slide, it's hard to do and annoying people like it"; and knockback KOs are "go flying, go boom" - game feel, defensive gameplay, or overarching moveset design mentalities are all a bit more abstract to explain and tend to be where games vary, you can call NASB1 fast, but you can't put into words just how fast it is; you can say Rivals has a minimal defensive system, but you can't easily summarise why that is (if a casual player even knows how to use defensive options in the first place). I don't mind non-sumo platfighters as a concept, I'd love to see a stamina game, but I think complaining about that being the crux of the genre is equivalent to being upset over all traditional fighters using lifebars, it's kinda just part of the genre and any break away is at the end of the day a gimmick, not an innovation.
I also think there's a third "similarity" here, but it has a weird... not nuance really, I'd say it's more completely irrational and unjustifiable but also kinda understandable at least in where it came from - the crossover element. People associate platform fighters as a "crossover genre" and aren't interested in playing a platfighter with new characters when they'd be happy to play any other genre with new faces - in the absence of Mario, people will accept a random furry they don't recognise in a platformer, but not in a platform fighter. Because of this, people end up not paying that much attention to non-crossover platfighters, and then wonder "why are all these games like Smash?" when exclusively talking about games that are more conceptually similar to Smash and therefore will typically edge more towards Smash philosophies. A self-fulfilling prophecy really
I'd argue a lot of it is decade-old debris from PSASBR - PSASBR tried really hard to avoid replicating Smash, while also being a lot of people's first non-Smash platform fighter (and if it wasn't they may have played a game with a lifebar system like Digimon Rumble Arena), so that may have set up an unreasonable expectation for those willing to give new platform fighters a chance, but on the other end, PSASBR was considered a flop, and had a bit of a console war sting attached to it, one that wouldn't exist if it was a Sega or Namco game, so it could have created a subconcious (or just concious) association between the genre and "wannabes". There's also a lot of two-decade-old Brawl discourse debris, especially considering how Melee tech has become a genre staple (even Royalty Free-For-All, which markets itself on how simple its controls are, and only has one comp-viable stage shown thus far out of a good many, has been said to have wavedashing by those who played it), but that probably goes without saying.
The most nuanced part of this discussion is sequels (Rivals and NASB particularly), which do end up implementing more elements from Smash - but even then, I have not played Rivals 2 nor read up much about it, but I can pretty safely say that NASB2 is nothing like any Smash game in gamefeel, even with air dodges; bubble shields; side inputs; and so forth. Yes, that includes Melee. Content is also another factor - CTR and Diddy Kong are both considered to be more advanced games than Mario Kart, but ask most people who prefer those over MK64 and they're much more likely to mention the adventure modes or unlockables... but story modes are in almost every platform fighter, they're roughly as common as wavedashing. So you're left with two things: unlockables, an outdated design philosophy literally only Smash still abides by, and giant rosters with a hypeillion characters, which is.... hahaha NO. Even if you sold an arm and a leg; got a kickstarter world record; or both, you're never gonna have as many characters as Smash unless you're doing a significant chunk of the work yourself. You'd have to either license out characters or hire artists to draw new ones, both of which are massive money sinks and only financially viable if you're to take sacrifices - less experienced character designers for OCs, less popular characters for ECs.
I don't really think marketing is a big factor to consider, because these platform fighters do tend to sell like hot cakes, especially when there's IP involved, which suggests they are at least being well-marketed (with NASB2 - which had godawful marketing for many reasons
(though the fandom isn't completely innocent in relation to this, even as someone who strongly believes the toxic state of Smash discourse is a consequence of its marketing and didn't intensify naturally) - as a particularly sore exception), what's really being "fought" for is 1. retention, and 2. respect, neither of which I really think matters outside of convincing bigger companies to work on or license platfighters.
