As we upload the files to the server only once and view them several times later or when we share the file to others, even others will have a look at the files. So doesn’t this make the system read heavy?
It is no as ready heavy as fb or insta. There could be lot of scenarios where you are using Dropbox as backup solution and you put 1GB files which gets written 250 (4mb chunks) times and only viewed a couple of times. So, overall they are saying it is 1:1 ratio. Checkout “How we scaled Dropbox” on YT.
What you describe is only the case of a few files.
When you have an entire directory synced with a cloud provider, the main purpose is archiving/backup, which means files being written once and read once for sync => same ratio.
If you’re like me and don’t sync it on other devices, this become a backup service only, which means files will be written/updated many times and read maybe once (if you need to recover your data).