While I see were you are coming from I don't really agree with you. The storage device you are purchasing is in fact 1TB in size but the file system that your OS uses rearranges that size to fit its needs. That is not the fault of the storage manufacturer.
It's not only due to the OS although you also lose some there due formatting and extra partitions. It's due to interpreting 1T, 1G, 1M, 1K differently.
1M is 1000 000
But in the computer world they use powers of 2:
1M is 1024 * 1024 or 1048 576 bytes (more bytes in 1M)
So what did the clever manufactures, they use the first (correct outside data storage world) meaning.
1M you get 1000 000 bytes but in powers of 1024 equal to:
1000 000 / 1024 /1024 = 0.953 MB
My disk has 488258 MB but I bought an 512GB??, 512 000 000 000 B
488258 * 1024 * 1024 = 511 975 620 608 Bytes, pretty close to 512GB
This is not really the same thing for GHz, it doesn't have powers of 2.
They could only change the meaning of boost but it still needs to have a useful meaning for the buyer.