Gorbachev gave up the Brenzhnev Doctrine in 1988. The Sinatra doctrine was the replacement and meant that Eastern Bloc countries could now determine their own policies; this eventually led to Hungary’s shift away from communism. The people of the GDR were motivated by Hungary and Poland's shift away from communism (allowed by Gorbachev's Sinatra doctrine) and so protested to bring down the Berlin Wall.
I think that Gorbachev may have had an indirect hand in the collapse of the Berlin Wall. However, the dissent in the Eastern Bloc nations and Soviet client states that led to revolution was decades in the making. It had simply grown so large that the oppressive police forces in the country could not control it any longer.
No Gorbachev did not cause the Berlin wall to collapse .
He was Russian president and as a Russian head , had his thoughts and opinions about
his neighbor Germany and it was like a nation has opinions about any other nations . He was too
busy revolutionizing Russia with perestroika and glasnost at that time . He did not interfere in other nations matter neither meddle with it .
Regardless of which leader held power at the time, stopping the destruction of the wall was a losing battle. There was too much international pressure. Even if someone else had been in power and managed to prolong the existence of the Berlin wall, it would have fallen eventually. The legacy would then belong to someone else. I think that Gorbachev was just as weary from the Cold War as the American government was. With the fall of the Soviet Union already on the books, the thought of keeping the wall up was not practical.
No, Gorbachev did not cause the Berlin Wall to collapse, because Regan's speech is what caused the Berlin Wall to collapse. In addition, the will of the people, who saw a better life in West Germany and wanted that life too, insisted that the Berlin Wall come down. Gorbachev might not have stopped it, but he didn't cause it.
Gorbachev did not cause the Berlin Wall to collapse, he simply oversaw a time in Russia and Eastern Europe that lead to more freedom. He did help usher in the freedom but I believe it is more important to say the people of the time caused the Berlin Wall to collapse, not just on specific person.