because I just hate other drinks
There is literally 'loads of money' to be made in manufacturing and selling soft drinks, especially the carbonated, fizzy ones. The actual liquid that is poured into bottles and cans in the factory costs less 1p / litre. They do spend on advertising but the really important factor is that drinking it makes you thirsty so you think you are craving more.
As a commercial product, it is indeed genius. As a way of looking after the basic needs of your body, it's really not great.
How do I know? I worked for them for nearly ten years. In the offices, the drinks were available on tap (like in pubs). Smaller offices had fridges with cans which were continually restocked. Loads of new plus all the classic flavours. All free while in the office.
You could tell when someone new joined, they would be very keen to try all the different flavours, know which one they liked best etc. after a week, at the most two, we would notice the new joiner finally having a glass of water because they had twigged that the soft drinks make you thirsty.
It's only the ads which make you think they are thirst quenching.
So it's really no surprise that you are struggling. My advice is to go cold turkey for a month, water only and just notice how you feel about water in that time
Remember, we make those ads on purpose to make you buy the product, which in fact makes you thirsty so you go on to buy more.
Laughing all the way to the bank at your expense.
Commercially it's genius. The people making those ads are drinking water.