It's not about the amount of money though. There's plenty of people out there supporting families on the National Living Wage.
The players point here is that if they get injured doing their job their outgoings don't change but the FA want their wages to be cut to statutory sick pay after 12 weeks. That's obviously unacceptable given the extremely high rate of at work injuries in the football industry and the fact that the clubs obviously don't make any adjustments to job roles to allow people with medical injuries to come back to work.
Football can't act like it's a normal business when they are placing demands on their worker's bodies that would be illegal in most jobs.