Planes were used in the world wars, then we have 9/11. This is the post 9/11 era where air travel sucks so much.
Similarly:
Drones are now being used in the Russo-Ukrainian war. Eventually, there will be a “9/11” with multiple coordinated drone attacks and then the way drones are treated will be forever changed. Civillian ownership of drones will likely be heavily restricted or entirely banned.
History rhymes.
You need compact explosives to effectively deliver by drone. The attacks you mentioned will typically use the homemade stuff that use fertiliser and is less compact (which is easier to deliver by van, as shown by Breivik and the guy that did the Oklahoma bombing).