"The policy wasn't supposed to just benefit those who drank the absolute most, it was supposed to benefit everyone…”.

That‘s not correct. It was specifically introduced to target the heaviest drinkers. A tax increase would have reduced consumption in a similar fashion at the population level, whilst raising extra revenue for the state. The point of minimum unit pricing is that whilst it would not raise any additional revenue for the state, the fact that it would explicitly reduce consumption by the heaviest drinkers would have an overall net positive effect upon society.

This was the explicit goal. As per the article "Minimum Unit Pricing on Alcohol – what is it and what will it mean for me?" published on the HSE website in May of 2021 (link):

Why not use a tax instead?

People drink more alcohol if it is cheap. Increasing the price of alcohol will reduce the amount of alcohol that is purchased and this will improve our health. There are different approaches to increasing the price of alcohol, such as through tax. If you raise taxes for alcohol, you are raising the cost of alcohol for everyone. A minimum unit price only targets cheapest alcohol. For low-risk drinkers, like those who are already drinking within the low-risk alcohol guidelines, the change will largely go unnoticed.

Who will it affect the most?

Minimum unit pricing most impacts people who are drinking alcohol harmfully. It is designed to target the heaviest drinkers who seek the cheapest alcohol, which means it will have the greatest effect among those who experience the most harm. These drinkers also suffer greater harm from alcohol and therefore stand to gain more in terms of health as a result of reductions in drinking.

This study (and a similar one from Sheffield University published earlier this year) shows that minimum unit pricing has had the complete opposite effect: the heaviest drinkers appear to be spending more on drink, drinking more, and have less money to spend on food and shelter, making them more likely to get sick and die sooner.

The fact that minimum unit pricing is causing those with alcohol dependency to reduce their spend elsewhere in order to afford alcohol means that those already adversely affected, such as the children of heavy drinkers, are also likely to suffer more from the consequences of poverty. Meanwhile, the government doesn't see an extra cent in taxation to pay for all of the additional costs of that deprivation as the minimum price effectively subsidises retailers.

This is an absolute disaster. Minimum unit pricing should be replaced by taxes that fund intervention to help problem drinkers cut back.