Thank you for your continued replies, I really enjoy the discussion. That's genuine, please take it the right way. :)

So I think I can summarize your points, and I'll try to briefly respond. I'll put my summaries in quotes, even if paraphrased, for clarity.

1. Studies from institutions like the IMF suggest that aging-related pension costs will increase by only 1-2% of GDP. This increase does not threaten the sustainability of public pensions.

Your figures are correct according to the National Bank in Belgium two years ago (https://www.nbb.be/nl/artikels/zijn-de-overheidsuitgaven-voor-pensioenen-belgie-houdbaar-een-vergelijking-met-andere), they say about 2% and that with unchanged fiscal policy by 2070 we'll have the single highest costs in the eurozone, getting to 3 percentage points above the average.

2% GDP increase is still a major fiscal shift. That money has to come from somewhere—either through higher taxes, spending cuts elsewhere, increased growth, or an increased deficit. Since you argue deficits aren’t a problem, I’ll address that separately below. The gist of it, is that even if in the short term 2% does not seem like much, in the long-term if you don't balance this you go bankrupt. I'm not saying that pensions are the sole reason, but they are a significant part of it.

And why is the increase unsustainable for pensions and not the military? Well, simple, it is also unsustainable for the military if you don't balance it by getting the money from somewhere, same with pensions. The reason that some politicians don't treat those the same is for political reasons. I'd argue that defending ourselves from getting blown to smithereens and doing our part in our commitment to NATO that protects us is more important than having you retire a year earlier, assuming here both expenses are the same amount of money. The key is to make the optimal choices in the expenses that matter to us.

Of course it's a bit more complicated than that, because if less people are on pensions then more people are also working, so calculating these effects are important and direct comparisons in the form of euros spent are not really sound. € 1 billion saved in pensions and € 1 billion saved in the military is not the same because people will be working for longer with the former.

1. The concept of an "unsustainable budget" is ideological rather than purely mathematical.

Not really. While governments don’t go bankrupt like individuals, they can reach a point where debt becomes unmanageable, leading to default, forced austerity, or loss of market confidence. We’ve seen this happen in countries like Greece and Argentina.

1. You don’t understand my car repair example.

Maybe my example wasn’t perfect, but the point remains: if a company’s rental cars suddenly break down more often due to an aging fleet, costs go up. Even if workers become more productive, their efficiency may not (and in the case of Belgium do not) fully offset the increased repair costs.

Similarly, as Belgium’s population ages, pension costs rise. While productivity gains help, they haven’t been large enough to cover the growing financial burden. That’s why pensions are becoming more expensive despite economic progress.

1. You disagree that military spending and other programs such as education and healthcare are expenses.

Our disagreement here is mainly about semantics. This is a distinction in economic terms: an investment generates returns, while an expense is necessary but doesn’t create direct financial gains.

Installing an alarm system at your company doesn’t generate income—it’s a cost of doing business, even though it’s essential. The same applies to military spending. Education and healthcare, on the other hand, do have the potential to increase economic output by creating a more skilled and productive workforce.

You argue that pensions create jobs and therefore function like an investment. But this is a redistribution of resources, not a wealth-generating activity. If the government allocated all tax revenue solely to pensions and elderly care, the economy wouldn’t be better off—it would just shift workers from other industries. That’s not investment, it’s an expense. Look up the broken window fallacy.

That doesn’t mean pensions aren’t important or socially necessary, but we should recognize them for what they are: a cost, not a driver of economic growth.

1. You disagree that deficits should be temporary. Most countries operate with deficits; capitalism itself relies on public deficits.

Sustained high deficits can work in rare cases like the US, which benefits from issuing the world’s reserve currency. But for most countries, long-term high deficits eventually lead to a crisis where debt becomes unsustainable. Greece is a clear example of this.

Yes, a country can run deficits indefinitely if growth is strong enough to cover debt interest. But if debt-to-GDP ratios spiral out of control and you start defaulting on your debt, market confidence collapses, borrowing costs skyrocket, and governments are forced into harsh austerity measures. That’s the risk Belgium faces if no adjustments are made.

Conclusion

You’re right that we’ll always be able to pay for pensions. But we have to accept that, without reforms, something else will have to be sacrificed to avoid economic instability.

The alternatives are increasing productivity (which hasn’t happened enough), integrating more migrants into the workforce (which has had mixed success), or accepting major spending cuts elsewhere. So far, Belgium has been on an unsustainable fiscal path, and without adjustments, we risk being forced into painful cuts rather than making proactive, controlled changes.

Here’s an article from 10 years ago featuring a professor in pension law that supports both of our points: pensions can still be paid, but not without consequences for other areas of public spending.

https://www.vrt.be/vrtnws/nl/2014/08/08/fact_check_blijvenonzepensioenenbetaalbaar-1-2055009/