They might be saving for bigger things, however this is a lot more than $3million. It's about holding the US economy hostage, as these will increase in frequency.
Indeed, stopping large-scale oil pipelines means US economy is held hostage, to a degree. Not all of it but some of it. Question is will it increase or not. This FBI action gives us some hope that criminals can be stopped.
Can be stopped? Doesn't sound like this is what happened here, the company paying the ransom is what stopped the hostage. The FBI simply recovered the ransom (and some more), but probably can't cover for the economic damage from the hold-up.