Most western terrorist attacks are by opportunistic losers who don’t have the knowledge or motivation to do something like this.

They’d rather drive a car into people who make them angry and use a gun they already own.

As for organized groups until recently there have been any good reason for an attack from any centrally organized group.

The lack of simple attacks on soft targets is proof that the threat is overstated and that a statistically overwhelming portion of humans simply don't want to put bombs on busses and rig them to explode on bridges or in tunnels.

Ukraine and Russia are western countries. Narco cartels have started using fpv drones, too.