I think we're seeing the unfolding of 37signals. I know that's the cliche thing to say here on HN, so note I say this bearing that overarching fact in mind.
I think Basecamp Next was the beginning. I can't put it into words, but users stopped praising 37signals after Basecamp Next. Changes were probably necessary, but it just doesn't garner the same respect as the original Basecamp. I feel like they deliberately removed private messages to get me on board with their CRM and it doesn't really seem like the average person knows what to expect when they add a user to a project (Can they see everything? Are they able to create projects?). Sure, I know, but the average person is reasonably unsettled by the current way this is handled - a problem that didn't exist in original Basecamp.
This Basecamp Personal feels like they are reaching, not innovating.
I'd love to hear what other people think, or why I am wrong and jumping to conclusions.
EDIT: Great comments. I am pretty dependant on Basecamp, so I don't relish the idea of 37signal's demise, but I have to be honest when I say I think they're concentrating on different ideals. I like most of Basecamp Next, but the things I don't like are glaring and 37signals is generally good at addressing glaring faults.
This follows something 37s has preached forever - turn your side effects into new businesses. They wrote blog posts, then turned them into a book. They had a lot of business customers, so they built a CRM, etc.
Here, they took a business product, got rid of free plans, and now can sell to a new kind of customer with their same codebase.
Also, a one-time charge for a SaaS app? That's something I haven't seen but could be applicable in a lot of places.
I will say, my employer uses Basecamp for several projects and I have a corporate Basecamp account, and so if I can get Basecamp for $25 one-time for myself and my own personal use, I might be tempted.