There's definitely a balance. Having too many conferences makes it confusing for attendees to know which one to go to, or forces them to pick one out of many that may apply to them.
It also takes time out of our engineers' schedules every time they need to create sessions, demos, practice, travel, etc. So there's a tradeoff between being able to get things done, being able to get as many experts to the events so you have access to them, and making it easy to make a decision on where to go in the first place.
Also TechDays is definitely still around: http://channel9.msdn.com/Events/TechDays/