A voice from the field here (Puglia, southern Italy). I can assure you that the landscape has changed drastically in a decade. Where a few years ago you could see immense expanses of green, now you see a ghostly landscape. It's incredible. Years and years have been spent inconclusively, both by politicians and by investigators, who have also wasted time with conspiracy theories.
Only a few people have replanted olive trees using species resistant to Xylella.