it should have been stopped with travel bans, isolation, testing, quarantine before it got out of hand .
I'm afraid that's the flaw in your argument. Once it becomes established in one area (China/Wuhan in this case) it is impossible - absolutely impossible - to stop it spreading world wide. All you can do is slow the rate of spread - you cannot stop it.
The World Health Organisation estimate that reducing air travel by 99.9% would slow the spread of the virus by 2 months.
Similarly reducing air travel by 90% would slow the spread of the virus by 2 weeks.
Personally I think this is going to go on for 6 months or so. All the Govt can hope to do is try to control the rate at which it spreads and hope they can prevent the NHS from collapsing under the load. If everyone caught it on day 1, then by day 7 we'd have 65 million people ill, and if just 5% of those need hospital care we'd be stuffed.
The point appears to be to 'allow' the public to catch the virus at a controlled rate. 95% of people will recover in 2 weeks without NHS involvement. Once enough people have recovered the hope is that those people can't catch it again, and therefore can't spread it to others.