I don't think Bale will leave this summer, although I doubt he'll be a Spurs player for more than another season after this one. Unlike Modric, Bale isn't pushing to leave, and that means Levy has no real pressure on him to sell. That combined with Levy "doing a Modric", by which I mean asking for such an extortionately inflated fee that he will price Bale out of people's budget, will mean he'll stay.
There's a couple of things that need to be considered here, by both Spurs/Levy and by Bale himself, as well as by the fans Firstly Bale....
....whilst he isn't pushing to leave he must realise the window of opportunity for him to join the likes of Real Madrid will not be open indefinitely. He must also realise that Levy is a calculating person who will look after himself/Spurs and doesn't actually give two shits about Bale. Bale will have seen how the Modric situation panned out, I've no doubt at all that what Modric said was true, that he had a "gentleman's agreement" with Levy (i.e. not documented, not legally binding, but a clear understanding) that he could leave the summer before he eventually did, and that the new, extremely lengthy contract, was signed with that agreement in mind. Modric was aiming to ensure Spurs got a "fair price" for him, and not a reduced one due to the shortened length of his contract. Levy then, promptly, denied the agreement and asked stupid money (in the £40m to £50m bracket) for Modric, money he was never likely to get and, ultimately forced Modric to remain at Spurs for another season, a season in which Spurs won nothing, didn't play in the Champion's League, and didn't qualify for the Champion's League. Bale simply can't trust Levy to do anything to help him.
Secondly Spurs......
Spurs must realise that Bale, as a commodity, has a shelf life. Will he be the same player in 18 months? Will he have regressed, plateaued, or worse picked up a nasty injury? They also need to realise that, based on the FFP they so love, clubs have less money available to spend on transfers. Ronaldo cost Real Madrid £90m, no-one will cost anything like that for the forseable future as, simply put, no-one will be able to spend that kind of money whilst also meeting their other costs AND staying within the FFP guidelines. Levy will likely want £50m for Bale, or something in that region. Will he get it under FFP? Probably not. Why would Madrid pay £50m for a player no-one else can afford anyway? If £35m or so is about the most anyone else can pay for a player, and still "break even" then why pay £15m on top of that for Bale? "Here you go Spurs, here's £35m. What, you want more? Well, good luck finding that team that can afford that, we'll be back at the end of the window when Bale is getting anxious, and no-one else has come close to offering you what you want."
Thirdly, the fans......
If Bale stays, will "top names" be added to support him? History would say no, Spurs haven't got a track record for adding real top names consistently. Occasionally there will be 1 who joins, but you're hardly in the same bracket as Chelsea, City or even United when it comes to bringing in elite players. So, is it worth keeping Bale, when the supporting cast will never be good enough for anything other that a tilt at 4th?
If Bale goes, will the funds be invested in the team? If Spurs have a £30m "warchest" and they manage to get £50m for Bale, are we looking at a warchest of £80m? Again, history would say no. Levy is, first and foremost, a business man, his business just so happens to be involved in professional football. In business the bottom line is king, is he going to spend £80m "gambling" on the returns (Champion's League football, trophies etc) or is he going to hold back £20m to £30m and keep the company in a healthy, solvent status? So, for the fans, it's almost a "damned if you do, damned if you don't" scenario. Keep Bale and the team isn't actually, as a collective group, good enough to win the title. Sell Bale and it's unlikely enough of the received funds will be invested in the team, thus leaving Spurs where they are now, not good enough to win the title.
