On the contrary: at this point all of that spending appears to have been a waste. Hezbollah neutralized, Syria regime-changed, Gaza in tatters, and now they've lost their nuclear program.
Imagine if they'd spent the money on education, or developing their economy. They could easily have reconciled with the U.S. if they stopped chanting "Death to America" and done something productive with their time and money. This was the inevitable result of their plans, and easily predictable.
They did spend a lot of the oil revenue on both education and developing their economy.
Compare them perhaps to Saudi Arabia, a similar sized country with much more oil and much fewer people. Saudi does not have any industry, does not export anything except hydrocarbons. All the extraction is done by foreign engineers.
Iran educates engineers, including many foreign students, has industry outside of oil, and largely works its own drilling and refinery. The Iranian economy is not dependent on migrant labor.
Saudi pays billions to Europe and America for high tech weaponry, yet can't defeat the Houthis. A considerable proportion of the money goes to baksheesh both for the Saudis themselves and their western suppliers. If Saudi decided tomorrow to challenge its Western backers in any real way, the umbrella would be withdrawn and the guys in the solid gold cars would last about a week.
Iran has wreaked havoc throughout the region for 40 years by putting $30 rifles, $200 RPGs, $100 IEDs and now, $2000 drones in the right (wrong) hands at the right time. They haven't lost a regular soldier in battle since the 1980s.
Even if you're calling the end of Iranian influence in the region right now, it's still an incredible run of hitting above one's weight. The only country in the Middle East this can be compared with is Israel, who are themselves legendary for hyper-insightful tactical leverage.
Iran spends a massive portion of its budget on military, which has ultimately amounted to nothing. The official budget is 10-15% of government spending, but the IRGC is mostly off-books, and likely to be at least 4x higher than the official budget states when counting just funds embezzled from public works projects [1] — since the official budget has about a third of all military spending going to the IRGC, this implies Iran's actual military expenditures are more like 30% or more of total government spending.
You can try a lot of mental contortions to justify it, but I think the simplest explanation is the cleanest: this forever war against Israel and America — the "little Satan" and the "great Satan" as they referred to them — was a catastrophic miscalculation. They should have spent the time and money elsewhere, and reconciled with America at least, and life would be better for Iranians if they had.
I’ve seen this Iranian engineer myth perpetuated ad nauseum on every social network for the last 24 hours and never before that, as if a desperate attempt to repaint the country as anything but a failed state. The reality is that Iran has been propped up by China and Russia for decades and has wasted all of its incoming capital on weapons and kickbacks rather than doing anything to boost its domestic situation.
Having lived in the U.S. my entire life, I’ve worked closely with many Iranian-born and -educated mathematicians, computer scientists, and software engineers. To OP’s point, I’ve never encountered anyone from Saudi Arabia in those fields.
Imagine if they'd spent the money on education, or developing their economy. They could easily have reconciled with the U.S. if they stopped chanting "Death to America" and done something productive with their time and money. This was the inevitable result of their plans, and easily predictable.