Just how long can Apple run the table in the post-Jobs era? It was simply a matter of time before those whispers turned into a question asked out loud. George Colony, the CEO of Forrester, a research and advisory firm that has followed the company as closely as anyone, is taking a particularly dim view of Apple’s future. In a blog post that was guaranteed to spark a conversation, Colony says Apple’s days as a market leader are numbered; its “momentum will carry it for 24-48 months” and then, absent a “charismatic leader” in the Jobs mold, it will devolve from “being a great company to being a good company.”

Colony doesn’t get too specific about what this means, but we know. It’s not just about market cap, or stock price or any other shareholder metric. Colony is talking about that combination of imagination and execution pixie dust that has made Apple the most significant high-tech company of the moment, and one of the most important ever.

It’s a pretty big statement, especially since Apple is on fire: $6 billion earned on $40 billion in revenues in the most recent quarter, the iPhone selling as briskly in the rest of the world now as it did in the United States for years, 65 million iPads sold in two years, more cash than it knows what to do with, and at least one analyst speculating that it’ll be a $1,000 stock before long.

It’s also not the toughest bet to make, since high-tech companies, in particular, almost always glow hot for only so long, with rare exceptions – especially after the charismatic founder leaves or is kicked out. We’ve seen it at Sony, Polaroid, Disney and even Apple, Colony argues, when Jobs was kicked out in 1985.

But it’s a sucker’s bet. Here’s the easy counter: There is virtually no chance Apple doesn’t have tricks up its sleeve that were developed in the Jobs era. And it’s those tricks, of course, that got them this far. They have something everyone can see: a management team in CEO Tim Cook and designer Jony Ive, handpicked by Jobs more than a decade ago. Indeed, Cult of Mac editor Leander Kahney says Ive is all the proof you need to know that Colony has it wrong: