No, he won't become 'immune' to them - they are supplements, not drugs. If anything, most supplements are cumulative - they work better the longer term.
I don't know the particular 'smart' brands you're using, but especially if the poor boy has joint issues already, a joint supp might be a good thing to keep up with.
As for a hoof supp, yes, of course nutrition plays a big part in healthy hooves. But as a rule, all horses are deficient/imbalanced in a wide range of nutrients, unless well supplemented. This is not just to do with the hoof department, and hooves, as with coat, are extremities which reflect overall health. So for these reasons, I tend to favour overall nutrition, rather than just hoof supps, with a few nutrients that may or may not be the problem. As I'm no nutritional expert, I personally subscribe to a great, fantastic value diet analysis/nutritional service called FeedXL.com & I recommend them. But there are other similar services out there, if you're interested but that one doesn't suit.
Re his feet, diet, as opposed to nutrition, plays a huge part in their health, and my bet is that if he was fed & grown 'too well', chances are that his diet was problematic for feet too. If he's not already, I'd advise you keep him on a very low carb(starch, sugar, grain...) diet.
Many other factors, such as environment & exercise - or lack of it - and of course quality & frequency of farriery, are also big contributors in the state of a horse's feet.