The real difference is in the concentration of actives and exposure time, not so much the brand. A drugstore hair mask from Pantene or SheaMoisture has similar ingredients to what salons use, but professionals usually apply products with higher concentrations (and pricier) that they leave on longer, sometimes with heat. That does speed up results, but if your hair isn't severely damaged, at-home masks work too - you just need to be more consistent and give it more weeks to see actual changes.
What you might not be seeing is because you're expecting dramatic changes really fast. A mask once a week for six months should've done something noticeable if your hair needed it (more shine, less frizz, more manageable), but it really depends on your hair type and how compromised it was. If you're still not noticing anything after several months, the product probably just isn't right for you - not that the routine itself is useless.
That said, going to the salon every month is honestly way too much money if it's just for a mask. But if you combine your at-home routine with a professional treatment every two or three months, you might see faster and more motivating results. Either way, don't stop doing masks at home; what you'd change is the product or frequency, not ditching the whole idea.