I'm sure that there must have been a few multi-car burn-ups in my lifetime, but I can't say I can remember a whole car park going up before a few years ago. Something must have changed. Google doesn't seem to be able to find any before 2015 either.
You haven't been paying enough attention to the subject, probably because lithium batteries were not around so no scare stories about them. Around 100,000 cars catch fire every year in this country, a large proportion of them diesel, and have done for decades. Having once been in the trade I also remember the occasional repair garages that burnt out.
Don't you remember the long Vauxhall Zafira saga, repeatedly catching fire and burning out from 2005 to 2019, Vauxhall despite recalls seemingly unable to get the root of the problem.
And the Liverpool, multi-story car park burnout taking 1400 cars with it was in 2017 when the Range Rover that cause it cannot have been a hybrid. Range Rovers had a number of recalls for that problem, diesel as well as petrol.
And how about all the diesel only buses burnt out in London, a big embarrassment for a while and plenty of photos on Google. We don't buy them any more, we now only buy zero emission buses, fully battery or hydrogen fuel cell or parallel hybrid.
I don't have to tell you of all people that all batteries are potentially dangerous. Most of those 100s of annual car fires are caused by wiring faults allowing 12 volt SLA car batteries to cause them, sometime in association with fuel seepages. Mostly starting under the bonnet, diesels burn out completely just as well as petrol cars once that fuel is heated.
So as shown and proved, vehicle burn outs are very common and not specifically an EV problem. The incidence of them will be somewhat higher with battery powered EVs than with i.c., but we'll get used to that, just as we got used to all those i.c. vehicle fires. Fire Brigades are having to learn not to try to put out EV fires but just allow controlled burns.
All new transport technology is dangerous at first but gets better. I'm from a time when scheduled airliners fell out of the sky with total loss of all on board a number of times every year. Now that is so rare we mostly forget it can happen when we fly.
Likewise EV safety will improve and in fact could be much, much better now, but for the risk taking attitudes of Elon Musk prompting some other makers to take the same risks to match the performance and range of his Teslas.
The company who made mine didn't take that irresponsible risk, so I'm supremely confident I will be as unaffected in future as I am after approaching six years of driving it.
.