It seems to me you're arguing both sides of the coin. Let me point out a couple basics to you. First, the in-game ones.
One, the Grid Overwatch Division is
not really out 'patrolling the matrix'. Think of all the cops in the world - now divide that by ten. And make them go 'patrol the internet'. It
really isn't all that effective. What is
apparently going to happen is that intrusion events - systems being decked - are going to red-flag to both the owning corporation and GOD deckers, who get to pursue the hacker no matter the jurisdiction. We've discussed the pros, cons, and 'cooperativity' of that in another thread - but it still isn't 'patrolling the Matrix' any more than responding to a silent alarm at a bank or liquor store is patrolling the streets.
Two, you ask this:
How do you coordinate all the corps to make that decision? Especially since not all of the corps are major players in computing, that seems like something only a few of the corps would benefit from and wouldn't get the other corps to cooperate with.
Simply put 'the Corporate Court does' in answer to your first question. In answer to the second, all of the the Big Ten have 'National Corporation' A-rated computer divisions at a
minimum; any other 'rated' corporation (A-AA) is going to have a division for their own proprietary code. No, Telestrian doesn't go down to Best Buy and get Renraku GridSamurai
TM firewalls for their systems; they have someone write it in-house. Sure, the baseline network code is going to be universal - that's what the Universal Matrix Standards meetings are all about.
Now for the 'RL' part.
Third, but most important,
we don't know. That information hasn't been released - plot or otherwise - which means we don't know
what is going on. You're asking us to justify one comparatively small tidbit of information by basically pulling theories out of our asses - and then shooting them down with questions and protests which, while good on the face of it, don't even comprehend the background of the game universe. Why the change? Because developers and writers have seen stuff that needs to be changed, I don't know. Because. The computer world today practically rewrites itself every two years - and anything more than
four years old is hopelessly out of date. A computer generation makes mayflies look long-lasting.
In-game, they're doing it because they're
really losing control over the network. Because right now, hackers are able to do to their systems damn near what the Echo Mirage team could do to their systems 40 years ago - walk through them almost as if they weren't there. You know what they did? They started researching ways to stop those people, and upgraded their systems, and changed the way the world works. Now, in order to get into Fuchi Americas without a passcode, you
had to plug your brain into a cyberdeck, just to be able to adapt your programs fast enough to counteract the stuff you never saw before, which they changed last week. And from the sense I'm getting, they're going back to that. Computers are speeding up. Trying to slice a network with a commlink in 2075 will be like trying to hack into NORAD using UNIVAC and running fraggin' punch-cards.
Things change. Security holes are exposed. If you have issues
regularly, you need to take a hard look at your system's core concepts. The stuff we're seeing is core-concept revisiting and revising.