Has the saying "I'm thankful for you, and forever will be" lost it's meaning?

When anyone unkonwn helps to another & help taker says to help giver,“I am thankful for you & i will be”.
Is this sentence true? I think it is not true for everyone,Because every help taker does not follow it in future.It’s only the matter of that instance only.Saying “I am thankful for you” People say this because they don’t have to say any other thing.Saying “I will be” after that it’s only nonsense & meaningless.