And it also doesn't make sense for a team to reject the best players, basically they need the best players for next season. Actually, Chelsea is in need of a young player whose talent is not much different from Lukaku, while Inter Milan and Juventus are still hoping to get Lukaku because they have also seen how Lukaku played last season in the Inter Milan team. So actually Chelsea also didn't reject Lukaku, it's just that they might need a younger player than Lukaku.
Coaches have qualifications regarding the players they are after and maybe Lukaku is not the type of attacker that Pochettino needs, especially since the style of play in the Premier League is known to rely on speed, while Lukaku is not as fast anymore Formerly. The difference is with Juventus or Inter Milan, maybe they need a player who has quality in the air and actually Lukaku has that. Apart from that Lukaku has made a big contribution to Inter Milan in the previous season and that is a big consideration as to why they want to keep him.
Every coach has a different strategy and when one coach doesn't want his services, it means he's not included in his plans and strategies for the next season. I don't want to say that Lukaku doesn't have quality, but his form has dropped and maybe it's age and frequent injuries that make him miss moments to show quality.