Theoretical communism is useless and this "no true Scotsman" argument is useless, at least for the foreseeable future.
How is communism going to handle malicious parties, since there's no ownership? How is communism going to handle needs for abstract needs, such as those for services? Marx didn't really think things through. You don't need strong AI, you need the singularity to centrally plan humanity. Until then you need to allow freedom of action for individual actors, i.e. rule of law + market economies.
The principles of communism aren't that different from capitalism, you work and get rewarded, the same way it happens right now. Communism is simply a system that places limits on individuals so that they do not exploit others and so they do not own the means of production. To avoid a concentration of resources/wealth for a small group of the population, because by just pure ownership and wealth such individuals can enslave humanity.
In my personal opinion, I don't think that if communism ever emerges it will be through forced means as it was before, I think it will occur naturally where Capitalism will simply fail in certain areas and the system will need to change.
For example say in 100 years, climate change causes enormous damage worldwide in various aspects of life. At this point perhaps governments will realize we can't just exploit raw resources, pollute and allow people to do what they want, so new economic systems emerge that utilize central planning and needs based production and distribution as to avoid harm, it will no longer be simply market driven. Just a rough example, of what could happen.
How is communism going to handle malicious parties, since there's no ownership? How is communism going to handle needs for abstract needs, such as those for services? Marx didn't really think things through. You don't need strong AI, you need the singularity to centrally plan humanity. Until then you need to allow freedom of action for individual actors, i.e. rule of law + market economies.