I simply can't see how that will work for such a long period. With all that unemployment and loss of income, people will be unable to afford basic necessities, social unrest sounds like a mild way to imagine the inevitable outcome.
Would it be feasible instead of starting and stopping lockdowns indefinitely, for countries to start ramping up their health care capacities*, gradually easing restrictions as the capacities increase until the systems can manage society returning to as regular as possible, while keeping the elderly and at-risk quarantined? Obviously it's not so simple, but to me it sounds preferable to attempting to run a country indefinitely at a fraction of it's prior economic level. This can't go on much longer.
*Build semi-permanent structures equipped solely for Covid-19. Other existing health care facilities will be kept for the regular health care.
I don't know if it's logistically impossible, or if it's just politically unpopular to tell the masses to go on with their lives as usual at their own risk.