My guess is that will happen some time before 2030, if western society as we know it continues to exist in a recognizable form for that long. 
Wages will be roughly the same by then, won't they? 
And wine cave warriors will concern troll the poor about their "bad choices" and look down on the demographic's health problems because they can't afford Whole Foods treats and have to lean on instant ramen and other food desert staples.
Two months after Yasi, bananas were being sold for up to $14.99 per kilo in fruit shops, while Coles and Woolworths were selling them for between $11.99 and $12.99/kg. The fruit was coming from northern NSW and the Atherton Tableland in north Queensland
https://australianfoodtimeline.com.au/cyclone-yasi/
It's one banana, how much could it weigh, a kilo?
Assuming we're strictly talking about the US, I'd guess a LITTLE longer than you - 10 years.
Are bananas made artificially cheap? Should the actual cost of bananas be something more than .40-.99 cents per LB?
Tropical fruit grown over 2000 miles away that's somehow cheaper than local apples? Yeah, I'm thinking it's a little backwards.
I suppose i should have given a small caveat - i live close to mexico. Produce is cheap here. I can go to a fruit stand and buy avocados for 75 cents each. Bananas by the lb are about .38 cents. Citrus, pineapple, coconut, chilis, peppers, onion, garlic, melons, and a few other things are cheaper here than the rest of the US.
Honestly i always assumed it was proximity to mexico.
"It's one banana. What's a banana? Eat your 1990s Canadian military rations or you'll starve to death, we have wreckage to pick through in the wasteland"
no banana 
will also be obsolete then 
