If a speculative bubble was later found to be a victim of pump and dump, then people also can go to jail.
At that point did it stop being a speculative bubble?
The reality is, reality doesn't have such distinct boundaries as you are trying to enforce.
At the end of the day, what is the point of a word's definition? To help communicate an idea to other people and society. The US financial and legal systems are intentionally designed to segregate the less educated. Confusion is their primary strategy to make more money! You can either choose to help them continue the segregation, or you can chose to liberate financial and legal concepts to everyone.
How can you help? By understanding what parts of the concept were easy to understand, what colloquial language is most used to describe it, and then realizing the gaps between the coloquial and technical definitions.
Trying to resolve those gaps with "you're using ponzi wrong" continues the segregation and confusion. Trying to resolve the gaps with "Oh.. you think a ponzi scheme is any scam using obfuscated financial instruments. Ok fair enough lets start the conversation there." you would then continue and say "A typical ponzi schema has a single power structure with a single voice and name e.g. Bernie Madoff. However, in this case it is a ponzi scheme with a distributed set of actors i.e. no one is working together, but still there is large scale issue occurring - we typically call this a speculative bubble / coordinated pump and dump - its not always easy to know what exactly is going on".
You could even continue "Realestate in general has actually been a generational pump and dump scheme. Its not that grandma's everywhere meant to harm anyone, but the common advise to 'buy a hose at any cost' is in favor of the realestate owning elderly (i.e. most of them) and as such is difficult for them to say anything else. Additionally, because its been generational, it seems to have been working for quite some time giving it even more credence. At the end of the day tho, it is a distributed ponzi scheme - if you go to withdraw your money and no one is willing to add even more money (i.e. how much you want, and the "processing fees" around it) - you will not get your money."