You're comparing one of United's worst periods in their history with one of Spurs's best and you still come out winning less trophies, 4 trophies to 0 the past decade.
Bottom line is Spurs have won two trophies (league cups) since Harry Kane has been alive.
You also fecked him over last year and are paying him peanuts compared to other world class players, earn £300k+ at United or keep being loyal to achieve a few top four finishes earning similar to what Jamie Vardy does, shouldn't be that hard a choice.
He's loyal though, so there's a chance, but to suggest Spurs are a more attractive destination than Manchester United in any metric is either stupidity or, well no, its just stupidity.