That's a bit unfair. Realistically, LG was more than a bit insane for Wizards. They had practically no control over what any region did. Regions could create almost no experience at all, or they might create sub-rules for how PCs could own property, throw online in-character parties, and let player in-character posts on forums drive region-changing events. That might be okay, until you couple that with what many new players would say: I can't make heads or tails of how to get started in this campaign, there is so much lore I'll never measure up to other PCs, I as a player can't get invited to these special events or if I do I am told I am doing it wrong, my region's admins seem to make special exceptions for people they know, etc. Administratively, it was a trainwreck. The Circle couldn't keep up with the work each region produced, couldn't accurately learn from what each region did, and couldn't provide the necessary help many regions wanted. From a corporate perspective, there was no way the company could shape the program properly to reflect new product offerings... there was too long a chain of people and too great a delay in communications from one end to the other.
That's really the LG problem. Everything wonderful about it for one player (usually an established player) was bad for someone else (usually a new player or Wizards). It is absolutely necessary that any new campaign try to learn from LG, but also that they change the experience in various ways to improve upon it and lessen the inequity and other issues.
It isn't as if this is a free ride for Wizards. In 2001, the RPGA reported in
Polyhedron that it had a budget exceeding $1 million, though they had requested almost twice that budget for 2001). They also shared that the RPGA had never been profitable. Every membership costs about $85 to fulfill. Costs have likely increased, and a recent job posting states the annual budget for all organized play (including Magic) is $6 million. Wizards has to be responsible with that cost and what it does for them, for the community, and for the hobby. There have been many years during which strong voices within Wizards (and TSR) argued for an end to organized play. I'm sure some of that continues. Monte Cook may or may not have been one of them, though
his comments here are just one of many threads of thought you hear from time to time arguing against organized play. Another common complaint is that 'giving away' adventures is bad for business. I'm all for organized play being challenged, but in some years it seems internal politics can cloud the benefits rather than sharpen a company's focus.
Will we ever have another program like LG? Nope, and we shouldn't. But, we can hopefully harness much of that magic and add new great things, such that we can have another organized play program that tens to hundreds of thousands will treasure.
When it comes to "shutdown the RPGA Network", I think a lot of that was because the term "RPGA" had a really negative connotation among gamers not already a part of it. I've had several experiences where I was running an RPGA game and someone came up looking for D&D. When they realized it was an RPGA game they left. They wouldn't even give it a chance. I think that perception is starting to change, in part because the name was dropped and became a more generic "organized play", which other companies also offer.
Edit: I don't want to softball this. There are great heroes at Wizards who have kept organized play alive when it could have been ended. And, overall, there is strong support for it right now. But, there have also been huge missteps. One of them was how WotC dropped all promotion of LFR, including having functioning links from the main web site to where players could learn about LFR and order/download adventures. The promotion early on was great, but really disappeared right around the time play and interest dropped. Coincidence? Hard to say, but I believe it was a big factor in LFR's decline. Hopefully WotC learns from these mistakes and from the excellent job Paizo has done constantly promoting its Pathfinder program (likely because they actually sell their organized play adventures).