Complex sentence: U2, their crew, and McGuinness thought that too much money had been invested to abort, and sympathised with the fans that had travelled to the venue in the poor weather; they decided to proceed with the concert as planned.
Split into simpler sentences: U2, their crew, and McGuinness thought that too much money had been invested to abort, and they sympathised with the fans that had travelled to the venue in the poor weather. Accordingly, they decided to proceed with the concert as planned.