I think Alonso had done his chances of getting a top drive a lot of harm by his outspokenness over the Honda engine.
Its OK for Mclaren to be good and Honda bad, but what about Merc and Ferrari? they come from the same shop.
Renault were not pleased with Horner, if the spectre of Alonso was there too it woud not be in their interest to "approve" him (not that they do approve RBR drivers, but it must be in their mind)
He would have done better to keep his head down
Nobody's going to not hire the best driver of his generation because they're afraid of criticism.
I don't see team managers falling over themselves and firing their drivers to hire Alonso because he is the best(your opinion).
They will be extremely stupid to do so and as someone said earlier Alonso needs a Top Team more than the Top Teams need him.
He needs to stay put at McLaren and possibly not demoralise some engineers like he successfully did during his stint in Ferrari.
McLaren is Alonso's 6th
team(Minardi, Renault, McLaren, Renault, Ferrari, McLaren).. that's a LOT for a driver of his reputation.
Teams will usually do all they can to retain their best drivers/players/riders. You will not see Messi/Ronaldo/Neymar/Neuer or Marquez/Lorenzo/Rossi constantly changing teams left and right.
There is something that Alonso really f*cked up and I don't believe we can all put it down to "bad luck".
I'm not sure any managers are going to be put off by the number of teams Alonso has had. He's been somewhat unlucky with his choices, it's true, but from a driving perspective there's little wrong with him.
Whether Alonso gets a chance to go anywhere depends entirely on how competitive the field is, IMO. If it's more of the same from the last three years, I don't see him having many options. If, however, things close up at the sharp end, then having a top driver like Alonso can make all the difference. If teams like Mercedes or Ferrari start seeing their WCC positions put at risk, I think they'll take a lot more interest in Alonso.
Having said that, I hope against hope that McLaren Honda sort themselves out. I think it's beyond sad that a team like McLaren has been in this situation for so long. It's easy to forget that they were once an absolute power in the sport, 2nd only to Ferrari in consistent competitiveness. Personally, I think F1 needs McLaren at the front again