Nah ancient virus strains can self-assemble back into functional molecules rather easily. They aren't "alive" in the same sense as bacteria and fungi, so they can stay almost-viable for a loooong time. It actually takes fairly active means to properly "destroy" a virus to the point that it cannot re-infect something compatible in the near future. Viral self-assembly is a proven thing, is rather common for the smaller-sized viral strains, and is one of the likely mutation vectors for them, . They're like SeaMonkeyes; just add water.
There were a few papers about exactly that kind of ancient stain re-emergence from viral self reassembly around 2012ish IIRC.
I didnt find any thing ref self assembly of viruses in the environment
and got side tracked by this little link. "Virus survival in the environment" Viruses stay viable for a lot longer than I thought https://www.oie.int/doc/ged/d8191.pdf . More than 3 years buried in the soil scrapie, the agent that causes mad cows, can still reinfect. I think I will go veggie.
Another thing that occurred to me, viruses are transmitted by hosts, there was an instance in England where plague was transmitted by flees. One village outside the plague area got the plague through, a package of cloths that came from a plague area. The priest quarantined the village and the plague didnt spread further. https://en.wikipedia...lliam_Mompesson