Yes, Honk. Many people today, including many bhikkhus, believe that some suttas have been altered or later added, for the reasons that you have mentioned.
As the Buddha realized just after attaining the Buddhahood, it is not easy for humans to understand the “previously unheard” aspects of Buddha Dhamma.
– Average humans cannot “see” the truth of many aspects of the foundations of Buddha Dhamma.
For example, our thoughts are generated not in the brain, but in the “mental body” or gandhabba.
– But because we cannot normally “see” the truth of that (because a gandhabba cannot be seen) most people reject the existence of a gandhabba.
– However, there are many occurrences that cannot be explained without the concept of a “mental body” that may come out of the physical body under some situations like Near-death Experience (NDE). Furthermore, now there are so many confirmed rebirth stories, which cannot be explained without a gandhabba being reborn many times with human bodies.
See, “Out-of-Body Experience (OBE) and Manōmaya Kāya” and “Evidence for Rebirth”
Please feel free to ask questions after reading those posts.
– We are aware of only a tiny fraction of our world.
– Even though scientists have “discovered” many things about the wider world in the past few hundred years, there is still much more to discover, especially about how our minds work.
– They are unable to explain how emotions like joy, sadness, etc can arise in a brain that is made of inert atoms and molecules. The mind can NEVER be explained with that approach.
– The mental body (gandhabba) is the key to explaining many things. Once one understands that, it is easy to see that “going through a wall” is easy with the “mental body” or gandhabba. See, “Ghost 1990 Movie – Good Depiction of Gandhabba Concept”