I think that's because he didn't have a lasting impact for Berlin (or Germany) beside being the first.
Zuse built the first computers in Berlin, but they were only used in the war-time government ministries afaik. After the war, he sold his first computer, which I would consider commercial available, to ETH Zurich in Switzerland. He founded 2 companies, but both were not successful compared to e.g. Intel. He would be really famous and well-known if he had managed to create a computing giant. He never had a university employment, so his papers were not well known compared to Turing and there weren't a lot of them. He even didn't publish his PhD thesis where he invented the first programming language and created an elaborate demo in which he programmed the first chess engine (also afaik). I think in science being the first is overrated and not that important. You have to publish and popularise your idea to really have an impact (schmidhuber would disagree). So his intellectual legacy was merely that he was the first, but not really influential. And his commercial success was also limited.
I think it's tragic, it was an enormous wasted potential for germany. It might be that he never was the great entrepreneur with the skills to build a tech-giant, but he was undoubtedly a genius who invented the future. He could have an enormous impact if he were equipped with a big lab and funding, if he would have taken the academic route. But Germany wasn't (and is still not) able to support geniuses that don't complete the usual strict path to professorship (study -> phd -> habilitation/post-doc).