Complex sentence: The tour ended pre-maturely as guitarist John Frusciante quit the band due to issues with the success of the band, for the remaining shows Arik Marshall replaced him but was fired from the band as soon as the tour ended.
Split into simpler sentences: The tour ended pre-maturely as guitarist John Frusciante quit the band due to issues with their growing success. For the remaining shows Arik Marshall replaced him but was fired from the band as soon as the tour ended.