Why downloading the game update files from launcher are not RESUME SUPPORTED!

Seriously, why should a company as a big scale as SE ignore this little but important point?
Currently the update content is divided into several parts (depends on the size of the Update) to be downloaded. (e.g B4 client)
BUT the problem is if you fail on a specific part, the download will begin from the start of that part, or if the patch have a single part (e.g. EA Update) you will totally fail no matter how Bytes you have downloaded.
As i failed 4times today and started over & over again from the beginning.
I haven't EVER seen ANY OTHER GAME to have a LAUNCHER WITH NO RESUME SUPPORT ability for its update files.
I don't want to justify! but there are many ppl not having imba connections. (which thery are not few ofc)
Imo it is totally inconvenience from SE by forgetting to implement such a basic ability.