Complex sentence: Since the crisis, the chaebol now have less debt so they are less vulnerable to similar crises, as was demonstrated in the 2008 crisis, but with the growth of the fewer remaining chaebols means they each occupy a larger portion of the economy.
Split into simpler sentences: Since the crisis, the chaebols now have less debt and are less vulnerable to similar crises, as was demonstrated in the 2008 crisis. With the growth of the fewer remaining chaebols however, each now occupies a larger portion of the economy.