Complex sentence: While this theory has success modeling consumption in the short term, attempts to apply this model over a longer time frame have led to the absolute income hypothesis falling out of favor as the consumption model of choice for economists.
Split into simpler sentences: While this theory has success modeling consumption in the short term, attempts to apply this model over a longer time frame have proven less successful. This has led to the absolute income hypothesis falling out of favor as the consumption model of choice for economists.