I think it has more to do with playing 30 odd big 'cup final' like games a season. Every game we play is a big game. In Spain teams can coast through the season with 6 or so big tough games.
That's a common misunderstanding you often hear: "The mid-table teams are better in the PL and the PL-teams play more games."
In England there are only two or three teams really playing for the title. The other 3 or 4 contenders actually only compete for the CL-spots. How many teams have a chance of winning the League after Newyear? One or two?
In Spain, Italy and even Germany and France, it is quite similar. You have Barca and Real who are the real contenders in Spain and teams like Atletico, Valencia, Sevilla play for the CL-spots (as do teams like Arsenal, Tottenham, Liverpool, Man U in England). Are they lesser teams than the English CL-contenders? I don't think so. The mid-table teams, Celta de Vigo, Athletic de Bilbao (remember ManU - Athletic), Sociedad, Villareal, ... are not worse than the mid-table teams in England. Same goes for Italy and even Germany (with the difference that they only have one title contender).
In the smaller leagues (Dutch, Belgian, Portuguese), the difference between topteams and small teams indeed is huge. How good would you think the best teams in those Leagues are, compared to English teams (Ajax, Anderlecht, Porto, Benfica, PSV)?
France is in between, I guess.
Any football game is 11 men v 11. Gent were organised and defended well.but very lucky in the second leg too. A corner that wasn't, an own goal and a red card!
Tottenham definitely has a better team than Gent, there is no question about that. Gent was indeed very lucky, but the own goal and the red card weren't due to (or thanks to) luck. (Gent also twice played without their best players.) But the difference in quality is much smaller than the difference in budget, because a lot of the players in the PL are not as good as many think they are.
BTW, the most expensive player Gent ever bought was the Japanese Kubo for 3,4 million euro's. He wasn't allowed to play. The 2nd most expensive player was the goalkeeper for 3 million euro's.