Why not? Why would you replace the drive if it is still working properly? Think about that. If the drive is fully functional what would you rather upgrade? You mobo and CPU or get a new SSD when your current one is working fine.Overall I agree, however I find it unlikely most of us will be using a 60GB or 120GB SSD in 5-7 years' time.
I know I plan on using this 120GB SSD till the day it dies, then and only then will I replace it with another SSD. I see no point in purchasing a new SSD when this one is functional. Knowing the limitations of the drive to begin with, why would I want to use it for anything other than an OS drive. If I currently have one in use for that purpose and it is working, then what is the point of replacing it with a larger drive, no matter how cheap they are, if you are just going to do an even swap and have to reinstall everything anyways?
So yes I do see people using them in that amount of time. Cause I dont see people jumping completely over to SSD anytime soon knowing that they could never possibly last as long as a mechanical drive. I still have my first HDD in operational order. It may only be 64MB in space, but it operates today. That is from a PC back in 1993. Almost 20 years later and still functions if I choose to use it. Cant say that about a SSD. So till SSD can match that kinda lifespan, I fully see people using them till they die.