For example, Housing isn't a problem, it's an investment opportunity. The people donating to your campaign wouldn't like it if their investments were pushed down in value.
An app can't fix your economy being dominated by bad actors.
crime- Is strongly correlated with poverty, which has been rapidly reduced globally thanks to technological innovation
Housing- Will be solved by tech making remote work viable and thus reducing demand in cities. Automation and some form of income stipend could also allow people to live in more affordable places rather than cities.
Your view of "tech" is pretty stunted if you only think web apps.
Remote work is viable, and yet the major tech companies are focused on hiring developers in a small number of overcrowded cities (or moving developers that it hires into those cities). I expect no solution to housing or remote work from them.
Small scale crime might be. White collar crime is adversely correlated, strongly, with poverty. And it sinks entire nations.