Footballers don't get up at 5 a.m. 6 days a week to practice their chosen sport, they generally work 9-12 with Mondays (if they've won) and afternoons off to do photo shoots, pose for video games etc.
Cyclists ride for hours and even days with cuts, grazes (Geraint Thomas rode the Tour de France for over 2 weeks with a fractured pelvis) and take it as part and parcel of their profession.
Rugby players get cuts, sprint off the pitch, get stitched up and race back on at the earliest opportunity. Footballers scream, roll around and feign injury for the merest of tackles, often in an attempt to get their opponents sent off, yet the authorities in charge of their game do nothing. Do that as a rugby player and the RFU would take a very dim view.
Footballers tend to abuse and harangue referees with little or no sanction. Other sports won't tolerate such behaviour.
Basically, it's all in the mindset. The likes of Tommy Smith, Terry Butcher and Stuart Pearce are relics, hard men of a bygone era when strong tackles were meted out and received in equal measure, without any theatrics, drama or screaming at the referee to issue a card.
English footballers in particular lack desire, commitment and a will to win whilst putting their body on the line, combined with no real interest in wearing their countries jersey with great pride.