I think it's a bit of a stretch to explain this using interest rates. I mean, for sure, low interest rates made it easy to collect a lot of capital and lure users into a "free" service. It doesn't explain why one would find this an acceptable and ethical form of doing business nevertheless.

It was clear from day one of low interest rates that those wouldn't stick around forever. This business model is a pile of s** that breaks itself.

It appears as if the most 'successful' business people actually don't think a lot about any kind of sustainability in their decisions. It's just about quick growth. And when push comes to shove, they wine that they aren't able to pay the bills anymore, because of 'evil' users who don't want to watch their crappy ads.