Get used to it, this will become much more common with climate change. Insect and diseases infestation and ecosystem collapse will be a weekly thing before you know it.
And really, agricultural collapse is quite separate from ecosystem collapse; agriculture is many ways defined by the intentional absence of ecosystem.
"Symptoms of X. fastidiosa diseases worsen during hot, dry periods in the summer: lack of water and maximum demand from a full canopy of leaves combined with symptoms due to disease stress infected plants to a breaking point. Cold winters can limit the spread of the disease;[8] as occurs in California, but not in regions with milder winters such as Brazil." (https://en.wikipedia.org/wiki/Xylella_fastidiosa#Environment)
It sounds like this could definitely be related to climate change. I'm sure monoculture agriculture doesn't help, but (based on quick searching) olive trees don't fruit in a commercially viable way until they are 7+ years old and don't reach peak yield until they are 70 years old.
If it was purely a monoculture issue, I'd question why it didn't happen sooner given the lead time necessary to increase production.
Crops undergo massive failures relatively frequently. Bananas are headed towards their second extinction this half-century. As stresses perhaps become more acute due to a rapidly changing climate and environment, this lack of resliliency may prove quite harmful, more so than the damage that can be reliably attributed to any individual stressor.
I did find a Nature article about it https://www.nature.com/articles/s41598-019-45365-y that was pretty useful. Seems to suggest it was a factor and may expand the effected range, but it is also an introduced disease and doesn't require climate change to impact large parts of the Mediterranean coast.
edit: You may be interested to know bananas didn't go extinct, per se. Mass market US bananas are propagated clones. We have bred the seeds out of bananas (with rare exceptions), so most large scale agricultural plants are tissue culture or cutting clones. The mass market variety was the Gros Michel/Big Mike, which you can still buy online easily. Panama Rust is adapting to the Cavendish, which was resistant when it became the new US mass market variety after the Cavendish. Greater availability of other varieties would be great. Neither of those are the best bananas out there (Nam Wah, Pisang Raja, and Blue Java are all great).
The history of bananas is quite interesting, and the future looks to be as well. While it did fall short of true extinction, I'm hopeful we can learn from past mistakes. Perhaps I'll have the opportunity to try one of the other cultivars someday.
We can play the “climate change causes everything bad” game for pretty much anything, but we’d be intellectually dishonest if we denied that climate change could actually have benefits.
This same bacteria causes Pierce's disease in Vitis vinifera, the common grape (from Eurasia). Whereas North American Vitis species are resistant to Xf.
There's a lot of research going into solving Pierce's disease here in the US from breading programs to bacteriophages. The later may end up helping solve the same problem in Olives.