Commercial coffee syrup shelf life mystery

I have connected some odd dots that grind my gears and I am looking for some input in this matter. I have gained about one year of experience in making coffee flavor syrups for myself and for my cafe. My current formula is a mix of concentrated fructose and glucose, protected with some sodium benzoate and potassium sorbate and acidified with a tiny amount of citric acid (I get to about a pH of 5). All those efforts were made to ensure I have a room temperature shelf stable product, both in storage and after unsealed that is relatively liquid and can be pumped with those cute bottle pumps.

I've noticed that most commercial syrups sold here (popular ones like 1883 and Monin for example) list "sugar, water, flavorings and citric acid". Most of them do not specify any sort of usage timeframe after unsealing and most of them have at least 1 year of sealed shelf life. I know for a fact, by trial and error, that you can't really go lower than a pH of 5 (at a 15% conc. in coffee it curdles the milk regardless if mixed before or after steaming). They are supposedly also made using only sucrose, so the sugar concentration should be capped to about 66%, which does not have a sufficiently safe water activity. They are most likely hot poured, however that can only guarantee the product's safety while sealed.

How can these syrups have such a long shelf life without lying about it's ingredient list? Do they just take the risk of assuming that a bottle would be used before it's unsealed shelf life?

P.S. I know the pH is pretty high for the benzoate to work properly but it's a compromise for milk texture.

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UPDATE: I've measured the pH of a Teisseire popcorn syrup (leaning to 6) and a 1883 vanilla and coconut syrup (both about 5). I've also found an old bottle of 1883 chai that was bought about 1 year ago and expires in 2025, giving it about 3 years of shelf life.