I travelled to Crete in 2008 with Kosmar Holidays just before XL went bust. The resort was extremely busy and all the hotels seemed full. I went there again in June this year and got the impression that the resort still hadn't recovered from the demise of XL.
There were lots of small apartment blocks and hotels stood empty, looking like they'd not been used for some time so I'd say that the void in Crete had not been filled by the other tour operators.
Most of the larger companies do not use the smaller hotels and apartments and most of the people in Crete were the non UK resident all inclusive brigade who go for a walk in an evening but do not spend a great deal of money in resort.
I hope
Icmeler does not suffer the same fate as this.