Not that I doubt specifically, but here's my problem:
If what you say is true, we wouldn't have the problems with the patent system that we have now. It should be mostly self-regulatory, with less trivialness since companies have an interest in each other's patents. This is clearly not the case, and as you can point to Apple or Microsoft, I can point to drug and agricultural companies that effectively pursue perpetual patents. Not all patents are created equal, and if you hold the keys to a cash cow, or a DNA sequence, that alone is worth more than any benefit from cross licensing. Prilosec earned over a billion dollars yearly while its patent was active. Now it earns about $300 million. And that's just one drug.
Not to mention you already stated patent has only been extended through treaty, and yet here we are with another treaty in the wings which no one wants to disclose the terms of, and would all but put any patent reform out of the reach of the courts or congress.
That should give everyone a moment of pause.