Buddha and Sankara of course were two of the greatest philosophers to have graced this planet. Another equally great, Bhagavan Aurobindo, said so
"Buddha and Sankara thought the world to be miserable, hence escape from it to them was the only Wisdom ( Escapism ? ). But then the world is Being, the world is Self, the world is Truth, the world is Ananda, prajna prasrutha purani, Omnipotent Wisdom created this world ! It is not the organised blunder of some Infinite Dreamer ! It is only our perception of the world though the mentalised ego which is the suffering. The world is nothing but Anantamaya Krishna, the Lord playing in the world as Sat Chit Ananda ".
Sankara was an illusionist. Buddha was a Nihilist ( Shoonyavadi ). Their arguments only prove their world class calibre. One doctrine is not against another. That is why we said all perspectives - atheism, agnosticism, Nilhilism, Absolutism, ( Poornavada ) - are all contained in Indian Philosophy, which displays the greatness of I P.
Hegel's Dialectical Idealism was reversed by Marx ( Dialectical Materialism ). Aurobindo integrated both Materialism and Idealism and called it Dialectical Integralism. He integrated Matter and Spirit. Matter is Brahman ( Padartham Brahma, Annam Brahma ) and is the outer garment of Spirit.
Matter is veiled somnambulist consciousness, which contains all the latent powers of the Spirit. Behind every atom, behind every molecule, there lies hidden and works unknown all the omniscience of the Eternal and the omnipotence of the Infinite. ( Aurobindo )
Spirit shall see thru Matter's gaze
Matter shall reveal the Spirit's face !
Aurobindo was a Realist !