New aircraft.
Great crew training and an exceptional safety record.
An entertaining CEO
1/ not always - their aircraft become older and older month after month, just like any other airlines. Some of them have more than 30 000 FH - first delivery of 737-800 in 2002...
2/ not always - young CPT with no special airmanship - but strong Ryanair corporate culture = SOP and SOP and... SOP. Reports of accidents/incidents can be found thru several aviation authority websites. But yes : no crash.
3/ the CEO doesn't love aviation - just cash.