I agree with what many of you have said, in fact I'd be surprised if they DIDN'T cut the conventions back to 2 days in the next year or 2. If they're going to the extremes of closing down branches and cutting the magazines in half, they'd be stupid not to cut costs in this area too.
I just attended one here in the UK, there were roughly 2600 LESS in attendance on the Friday than there were on the Sunday afternoon. I spent a lot of time during the sessions wandering about, and so did 100s of other attendees. The local MacDonalds was full of them every time I walked past during the sessions. People were getting up and coming back with a load of coffees for everyone in their group shamelessly during the program. It's obviously too long for most to pay attention to even after shortening the program and making every talk shorter to keep them interested.
I think rented venues are causing problems too. At the one I attended there was a crazy amount of brothers attending. It could only be because of strict health/safety/security rules imposed by the venue. At one point I stood out in a corridor where you couldn't hear anything of the convention and counted 15 JWs working as attendants, standing around talking in groups of 2 or 3. Walk further around the corridor and you'd see 15 more. They even had to resort to having sisters attending, probably the same amount as they had brothers.
Also, if their game plan is to keep JW kids in and get them heading for baptism, forcing them to sit through 3 days of a mind-numbingly boring DC is NOT the way to go about it.
And they definitely neglected to mention anything about next years conventions at this one. All of the conventions are being shuffled around in my area, getting smaller and cheaper by the year. I don't think anyone would be surprised or particularly suspicious if they announced there were going to be 2 day conventions in assembly halls next year.