Complex sentence: Although there are reasonable arguments that Kasparov could have won over the Deep Blue if Kasparov had played up to his level, more sophisticated chess programs soon decisively outmatched humans and the Deep Blue versus Garry Kasparov match is cited as the symbolic turning point.
Split into simpler sentences: Although there are reasonable arguments that Kasparov could have won over the Deep Blue if Kasparov had played up to his level. More sophisticated chess programs soon decisively outmatched humans and the Deep Blue versus Garry Kasparov match is cited as the symbolic turning point.