The article actually addressed this and apparently they are even developing some resistance to diatomaceous earth. The only sure fire treatments described are extreme heat or cold. It's a pretty horrifying situation we've made for ourselves.
Also, the fumigation packets for livestock stalls, but you need to duck tape your contractor bags of clothes, etc. closed and leave them outside for 6-10 days.
I once had a pretty bad bed bug infestation and tested DE by putting a bedbug in a cup of it... It lived for weeks before I killed it by hand. DE only hinders their movement in my experience, you need stronger stuff to kill them.
Cedar oil literally melts them. After weeks of trying everything we could get our hands on ($$$ gone), I tried straight up cedar oil in a spray bottle and found immediate delight in watching those motherfuckers writhe in agony as they shriveled and died. The others tried helplessly to flee, but I was undaunted and hunted them down, one by one. None lived to tell the tale, and all were chemically dessicated and vacuumed up.
They already have evolved resistance to the chemicals we use to kill them, hence the resurgence.
Edit: from todays Morningbrew:
It’s possible that France really is suffering from a bedbug epidemic. The critters have been making a comeback globally in recent decades after being nearly eradicated in the 1950s using pesticides. Bedbugs have since developed a resistance to these chemicals, and high levels of international travel also haven’t helped.
However, French exterminators are saying that the public might be overreacting.
The creator of the pest control website badbugs.fr told the BBC that 75% of bedbug inquiries his company receives are false alarms.
Normandy-based pest controller Romain Morzaderc explained to the Ouest-France newspaper that in 99% of cases, other “nasty black insects” get mistaken for bedbugs.
There's also the fact that we quit using DDT in most of our insecticides and DDT was great at killing bed bugs it just was also cancer causing in humans.
But the main reason why it’s boom time for bedbugs, according to the review, is that they’ve evolved resistance to many pesticides, our main line of defense. Indeed, these critters are now resistant to “most of the major classes of insecticides,” the review states, including pyrethroids, which is still one of the most commonly used insecticides. They’ve also developed resistance to DDT, which attacks insects in a similar way to pyrethroids.