Zelda could've been a massive franchise, had OOT been pulled off. However, an interesting downside might just have occurred, had it pulled through.
Going through the N64 and Gamecube years, Nintendo had to fill the void left by losing their biggest IP after Mario (and arguably Pokémon). The SNES, despite that parasite of plastic and silicon, won the 16-bit era through it's library of games, and Nintendo needed games like Link to the Past if it was going to survive against Sony. It sent them into overdrive, sending creative assets and funding to its other franchises, to help boost up their fanbases and cover the sales losses from Zelda.
I once heard a quote from Myamoto during the SNES years that Mario should focus on level design and gameplay, story and worldbuilding was for Zelda. Would the Mario RPGs and other 'story-heavy' games, all excellent, have been made, had LoZ been around? Would 2005 have been the Year of Peach, an event that turned gamings stock 'damsel in distress' into a vibrant character second in lovebility only to Luigi, had Zelda been around to be the Princess with a Personality? How about everyone else in the Nintendo roster? Samus? Pit? Kirby? Aster & STA-C? Fox? Falcon? Half a dozen others from Pikmen to Animal Village to Game & Watch Inc.? How many would've been gutted for Link? Even if those Zelda games were brilliant, it still feels weird to imagine how any of those we have IOTL might not have been made. Zelda would where right now, it's tenth/fifteenth main series iteration? List me ten to fifteen OTL big games you'd be glad to see never happen. I bet you'd make it to five.