They're stuck in the past. Sure they're a big enough name but most young players today were barely born or following football the last time the rags were a consistently successful team. Some 20 year old player from overseas (or even from the UK) doesn't give a fuck about the rags in the same way the media want them to. They didn't grow up with the rags being the team that the media are yearning for. My nephew was born in Spain, he's a teenager and in the Atletico Madrid academy. The rags are an irrelevance to him as a football fan, when he talks about English football, its always City, Liverpool and also Arsenal now. He just sees the rags in the same way we probably see Real Sociedad, because hes never known them to be a majorly successful team, nor has he had it drilled into him that they're still a big deal like we get in the media in the UK.
Most older top players like Kane have no interest in joining them while they still have ambitions as a player, they're often not even a champions league team. Did they think Kane was leaving Spurs where he's a legend to go to another domestic team and probably play in the UEFA cup again? And younger top players don't see the rags as a great team, as I talked about above. So what you're left with in terms of options is mercenaries on their last legs like Casemiro, or young players that are probably not the best of the best, because the best are being snapped up by real champions league contenders.