Lockdown in it's current form isn't going to continue indefinitely so don't worry about that. Personally I see the whole getting on with life/economy versus a different aim of trying to suppress the virus as a false opposition. Because the case numbers grow exponentially when R is over one, schooling and economic activity, mental health etc will all be affected as much if not more by no lockdown as the are by lockdown. It's the existence of the virus that is causing the problem.
Globally no government is locking down for fun or because they want to, or even because they just want to prevent covid spread and deaths. I don't think so anyway. They are doing it because they can see that exponential growth of the virus not only kills but destroys all those other things we are missing in lockdown.
Given where we are, lockdown is the only way to get to a state of reopening. And we will start to get there OP, it looks like a very bumpy road but they are going to be trying incredibly hard to open up everything they can to keep R below one. Remember if it is isn't below one, there won't likely be any schooling or much economic activity. The numbers of young and fit people who die or are sick and off work for a long time may seem a small percentage, but if you think in terms of 70% odd getting it..that is a lot of people. I am not saying their lives are of more value, but you mentioned youth/fitness etc so just pointing it out.
My anger is less directed at lockdown itself than at things like, are they going to handle it right and make sure to enforce/ease at the most effective times? But more than that, I am angry about why the outbreak occurred and spread in the first place and specifically about why the UK outbreak was allowed to get so bad before measures were taken, especially the virtual ignoring of the influx of Italy returnees. I don't claim to understand it fully and I could be wrong, but it really does seem that we had a chance to start controlling this when we had much lower case numbers and that would have meant a shorter time needed in lockdown.
I hope things can get back on track as safely as possible for everyone soon.