Not all people are capable of donating. Or some people faint one millisecond after they see a needle or their own blood. Well, it's a thing that you should do but you can't force someone to do that. It costs you nothing and your blood will be used to save people.
tbh i tried to register back in 2017 but somehow they fucked up paperwork or some shit and i never got cleared to donate blood that's how it works you send off a sample of blood and if cleared you can donate hell you can donate blood from 18 into your 60s and with Corona you can't really register right now it's every 3 months in normal times whenever this corona mess clears i will try again
Why don't they pay people to donate blood? When you donate they give you a thank you card, and that's it. If they need it so bad they should incentivize it.
By the way there are rich people who pay for young people's blood to be injected into them. That's a new job for you mens sell your blood to old rich people