The Houthis operate under few constraints. Combined with the strategic capabilities Iran has provided them over the years, this has transformed them from a localized Yemeni threat into a first-order regional strategic challenger.
Houthi’s could invade Iran and conquer it given enough resources. These guys are warriors. They don’t sit in front of TV and give nauseating speeches. Their soldiers don’t even carry smart phones or sit on social media boasting about their presence.
What doomed Hezbollah, Iraqi Miltias, and IRGC is they were all lead by pacifist generals/leaders. All the capable ones died in battle. The current lot are those who spent too much time citing poems and quoting philosophy. Houthi’s understand this. That’s why they take Iranian engineers and weapons and whenever Iran gives advice it goes STRAIGHT TO THE TRASH.