Hmmmmmm.... First off, I don't like the term " myth". You could have replaced it with "question" and not been so dirogitory.
Next, is there some reason to believe that you have any more answers than others in the forum? You are not an employee of Cakewalk I assume.
As to your points
1. I agree it is unlikely.
2. I don't recall seeing anyone suggesting content would be taken away, just no new added content would be provided. I think that is likely.
3. I believe Cakewalk when they state "Core". My interpretation is that "Core" refers to the engine all three models(Platinum, Professional, Artist) use. In fact, all nine new enhancements in the rolling updates are for all models. So, while you get to keep Drum Replacer etc. do not expect unpaid updates to them.
4. As you stated, we do not know Cakewalk's financials. That also assumes we don't know if they are in financial difficulty. As to the " offer to reward loyal customers" this is only true as part of a financial plan. Having been technical support for sales and marketing for a high tech firm for 20 years, I assure you that in all the countless sales meetings just rewarding customers never entered anyone's mind. The meetings centered around making money . Usually by either reducing costs or raising revenues. I am confident that this "reward" fits into the latter category.
Still, I find the offer for lifetime core improvements to be compelling. I will be taking Cakewalk up on the offer.