People would go mental and it's just not feasible.
How do they get food. How do they get toiletries etc?
Not everyone has been hoarding like the world's been ending for the last two weeks.
And there's no evidence it'd actually work in terms of reducing the infection. All we know is the virus is here and literally anyone could have it and we wouldn't know.
So you could sit in a house for two weeks and have it and infect all your family and vice versa. Then you're all just in one big/little coronary house breathing each others' illness in and that, if anything, is going to make people a lot more ill.
On the news this afternoon, there was an expert stressing how important fresh air is for people who are self-isolating and how the virus doesn't actually spread that much outside, as long as people keep their distance.
Plus, once that two weeks is up, the virus would still be here. Everyone would come back out and then if they didn't get ill in that two weeks they'd just get it then and you're back to square one.
The best example we have so far is Singapore and they didn't do anything like that. They simply tested, tested and tested and banned large gatherings. They only shut schools if there was a case reported at that school. As of yesterday, a very low number of cases and zero deaths (that may have changed on the death toll today, I haven't seen).