The Great Dao was ruthless, without thought, feeling, or life, eternally one and unchanging.
When the Great Luo Dao replaced the Great Dao of the Heavens as the foundation and supreme principle of all things, it would fall into that same state.
Under any circumstances, to all that existed and all that did not, the Great Dao was utterly lifeless matter, the Absolute Void.
Even the so-called Heavenly Dao Will did not mean that the Great Dao had gained sentience. Lord Gods like those in the After Ascension world were Incarnations of the Laws, but the Laws they represented had no thoughts or will of their own.
If it were merely a matter of Dao Union, then given Meng Chuan's standing and strength after his final Ultimate Sublimation, the Great Dao of the Heavens could not extinguish his thoughts and will.
For the Great Dao of the Heavens was not, in essence, higher or stronger than his Great Luo Dao, let alone stronger than him after his Ultimate Sublimation.
It was like the tales of Hongjun's Dao Union, legends and anecdotes whose truth could no longer be verified.
Hongjun had united with a Heavenly Dao stronger than himself, yet he had retained his own will rather than being wholly assimilated by that more powerful, higher Heavenly Dao.
How much less could the Great Dao of the Heavens assimilate Meng Chuan?
Of course, the Heavenly Dao and the Great Dao were different.
The Heavenly Dao had a will. Though impartial and utterly fair, cold and ruthless, a Heavenly Dao Will did indeed exist.
The Great Dao, by contrast, had always been and would always be without one. It simply operated in silence. Whether it came into being, perished, or was even destroyed by someone, it would show no fluctuation or response.