I've spent a similar amount as you on Airbnb as a hotel replacement over the years. I have the same exact feedback. What started as a great community vibe is now being exploited by slum lords. It's really a shame, the site is a victim of its own success.

I have to believe that with better curation it would have been possible to maintain quality. For example, Lyft still has a great UX with awesome drivers like they did at the beginning, even after they have scaled up to MegaCorp status. It seems Airbnb has made a conscious decision to pursue growth at all costs, including what made them great in the beginning. Time will tell if that was a smart play.