I'm in Queensland. There is an international travel ban. No foreigners can enter Australia and we can't leave unless there is an exemption. The state borders are also currently closed. Anyone returning has to quarantine.
We have had 6 deaths over the whole pandemic. Our daily lives are pretty much back to normal. Lockdown works!
I agree that it would be difficult to get people in the UK to comply with a lockdown now, especially since Boris has been telling people to get back to the office and Dominic Cummings has been running about doing whatever the fuck he wants. But it's not true to say that lockdowns are futile.
What happens here long term in terms of travel is definitely a concern, but we can't just open the floodgates to the rest of the world.
I'd be happy to do another lockdown if the cases rose again.