Hero had way bigger buzz, it was presented like a big movie, debut of 2 stations, industry supported them big way, then comes the fact that it was a remake and the song was hit too, in short from all angles Hero was presented as something important to audience, followed almost all things people use to launch a starkid or a newcomer in general, they make them look like big deal, their movies look like big deal and give audience a reason to care.
Comparison wise, Loveyatri was much smaller, despite Salman promoting it, it wasn't presented as big deal, the lead actor doesn't look like lead hero, it looked like it's just for the sake of relationship, the public perception was that Salman is just launching his relative, no one took it seriously, almost no buzz and looked like some timepass project, rather then a serious attempt at launching newcomers, why would audience care then, and they didn't.