The Abhidhamma is a highly intellectual theory of nature for sure. I have not seen any other theory/philosophy that explains the conscious experience to such a great depth. Bhikkhu Bodhi does acknowledge that Buddha’s dhamma is the foundation of Abhidhamma even though he doesn’t seem fully convinced that Buddha taught it to devas in tavatimsa realm and gave a summary of each discourse to Sariputta.
Dr. Lal, you wrote: “Detecting/experiencing a single citta or a suddhāṭṭhaka is possible only for a Buddha. Anyone else, including Arahants, cannot do that.” Why exactly are you so confident that no one other than Buddha, not even Arahants can discover those aspects of Nature? If Arahants recited the finalized Abhidhamma, should it not be explicitly mentioned that this is the work of Buddha? Interestingly, it also doesn’t seem mentioned anywhere in the Tipitaka that “Abhidhamma is a later addition which was invented by bhikkhus” or something like that. If Arahants recited the completed Abhidhamma, they would have directly mentioned that it is not Buddha’s work if it wasn’t. It looks like they neither clearly mention Buddha taught it nor he didn’t.
I wish resolving this issue was easier. I’m just curious because I want to figure out the truth for myself. Maybe you could share your thought process a little more which I’m sure will be beneficial to me and others who read this.