There has been a lot of progress in AI research, and AlphaGo does represent some of that. But AlphaGo is not any kind of progress from the AI before it towards

There has been a lot of progress in AI research, and AlphaGo does represent some of that. But AlphaGo is not any kind of progress from the AI before it towards AGI. It's progress, but progress mostly perpendicular to the goal of "true" or "general" intelligence. It's similar to the same kind of AI that was built for chess, just for a much more difficult problem in that same class of problems. No problems useful to general intelligence were solved in making AlphaGo, just harder problems in the field of special intelligence. It's still a tremendous accomplishment, just not one that puts AGI happening within any of our lifetimes.