Not quite sure I understand the model being proposed. It sounds to be one that is selective, and only passable by those who are willing and able. It's not mass-conscription in the conventional sense.
Surely we already have something similar in the UK with the Reserves; who also take people in their 50s, particularly if you have some useful military experience.
Sweden has a population of only 9.5m; and its armed forces consist of approx 20k soldiers; 20k guards and 10 k reservists (ages 16 -70). I'm not surprised that they want to inculcate more military skills in their population with Putin on the prowl.
Swedish towns told to 'make preparations regarding the threat of war and conflict' with Russia