The economic concerns of growth accererated clones

Now I understand Palpatine's plan perfectly. He knew he would need clones in ten years to fight the war and he needed adults. Yet everyone seems to ignore this fact. If they are growth accerated, not only do they grow in half the time, they live half a normal life. Growth acceration cannot just stop. So they are spending a lot of money on every single clone and these guys only last a couple years each. I mean their entire life time is probably around 40 to 50 years. Yet most of that would be too old to fight. So how long would these clones be able to see combat? They leave Kamino in their 20s.
They age so quickly that they don't have much time on the front lines.

Thats not a big deal in the story because the clone wars only last a few years and then they have stormtroopers. I think it is fair to say that the Stromtroopers are recruits as well as clones. I believe that the reason for the change is that Stormtroopers are a better investment then the clones.

Did the people of Kamino think of this? It just seems sort of funny to invest so greatly in something not really worth it.
I guess in the end it is worth it because Palpatine builds the Empire. I just wonder if Senate ever brought up the matter over the amount they are spending on something which can only last a few years.

-Seldon