For me its more to do with players like Souness and others from that era saying they'd love to play against him. Yes, going by the rules in the 80's Jack would be kicked off the pitch before half time. However I'm pretty sure Jack would love to play against someone with Souness mindset, as by todays rules he would be in the book after 5 minutes and walking a tightrope for the rest of the game.
A lot of the older pundits seem to ignore the fact the game has changed considerably, even over the last 15 years. Not saying its for the better, but the type of challenges Siouness would put in, are only seen in a Sunday morning league these days