The difference with Uber is that it requires a lot more trust to give someone access to your home while you're away to clean it. Not sure I would want to subscribe to a service where I would have to trust any local dude to visit my home. It's like a nanny. Picking someone to look after your kid is a very personal thing. It's not a lowest bidder thing.
I do agree there was a trust issue with Homejoy (I've personally tried them once and had similar concerns). But, I don't believe the issue was that they were in an unviable business where trust can't be gained, but rather they didn't have the right mechanics in place that help develop the necessary trust between the consumer and the cleaners.