Most of the decent vaccines are already well progressing through stage 3. So I think its days are numbered. I do think we will get a second wave, but I don't think it will be such a big impact. The UK was fairly rapidly infected from overseas travellers during January and February. Some 1-2k unique entrants busy spreading unchecked/unknowingly for most. When we locked down, our R rate must have been huge. People are a lot better educated now, even the stupid ones.
I do think lockdown could have been targeted by vulnerability. Time will tell, but the massive impact on the economy will probably not have been worth the lives which may or may not have been saved. At the end of the day, lockdown was not to reduce deaths it was to avoid overwhelming the NHS. Under 45s could have mostly avoided lockdown without impacting the NHS and the impact on the economy would have been significantly less.