The UK government never committed to eradication and the lockdowns were weak in various ways, so only draconian in a pretty superficial way in many cases. Official UK government scientific advisors have not set themselves up for the 'pipe dream' stuff you mention because they often said that total eradication wasnt really an option, and that did not suddenly change once UK abandoned its especially crappy plan A, a plan which by the sounds of it would have been more to your taste.
Its somewhat hard to judge the effectiveness of many lockdowns because they were done rather late and failed to avoid a lot of the initial exposure of the vulnerable to the virus. But its clear that governments are mostly going to be proactive now and not make the same mistakes most of them made in the first months. So they will be cautious, which is the right approach. If at some point hospitalisations and deaths remained low in a situation where there were an absolutely huge number of infections taking place, then of course the equation will change and governments will change approach again.