Why doesn't Twitter properly support multiple accounts?

It baffles me why a cellphone number must only be linked to a single Twitter account.

I have a good use for multiple accounts, and I'd like to be able to get to them all on the same phone. Twitter makes that impossible, even though it seems like it shouldn't be.

Say I have a personal feed (call it "myfeed") and a work feed (call it "myworkfeed"); I'd like to be able to receive both on the same cellphone. Implementing a simple "switch" command would allow you to send tweets to one account or another from the cell phone ("switch myworkfeed" would make all subsequent tweets from my cell phone go to my work feed; "switch myfeed" would direct them to my personal feed). Twitter could flag which feed the tweets were coming from by simply prefixing them with [myfeed] or [myworkfeed] or whatever.

This shouldn't be so difficult, and it would make my life considerably easier. If Twitter is concerned about fraudulent sock-puppets (and it might well be), then putting an "Associated with" line in the profile would suffice; all the other accounts linked to that phone number would appear, and then detecting sock-puppets would be easy.

How about it, Twitter?

---Ken