Seems to me the game designers can look at the while process right from training to use mining barges and strip miners right through to manufacturing the 'best' items (for whatever value of best you deem appropriate) and they can decide what time sink should be required in total for any given outcome and, further, how that time sink should be split at each stage in the process.

Since there is no time sink in reprocessing I can only assume that the need for refining is only in the game to manage cargo size. Miners mine big things, which limit how much they can do without a fleet or alt hauler, or by jet can mining. These big things are a pain to transport all over the place so refining is added to turn them into small things which are easier to transport. The time sink to obtain these minerals is all in the mining activity and associated skills, with bonus materials for going through the refining skills time sink.

words

...you can smelt millions of tons of ore instantly...

Not everything in EVE makes sense. This applies to most video games. It makes them fun.

Mining is already boring and profitless enough as it is. Don't ask me to spend hours mining ore and then have to wait for the minerals to refine.

The difference between refining modules/ore and manufacturing is that you can't make much of a profit from buying stuff and refining it.

You must be SO much fun to be stuck in a lift with

Updating/placing new market orders should require complete paperwork to be filled with the Station broker. It's a team but there are only let's say 12 available at any given time in a single station.

That would totally be a fun mechanic.

EDIT : A whole new meta of "station camping" would be born.

Also we should have to file a comprehensive flight plan every time we plan to undock that lists all the systems we will be passing through on route to our destination. Processing times will vary between 2 and 4 hours after which you will be allowed to undock.

Hilarious excerpts from "my first sarcastic comment", medium: crayola #4 on paper. Fantastic.

Remember, this would not have to require any extra clicks. You would still be going from 'clicks' to 'get bacon', just with a time delay. But that little delay would increase the value of people with so-so refining skills by a lot. At the moment they break the rule of "you can still be useful with less than optimal skills" that Eve values dearly.

Hilarious excerpts from "my first sarcastic comment", medium: crayola #4 on paper. Fantastic.

Remember, this would not have to require any extra clicks. You would still be going from 'clicks' to 'get bacon', just with a time delay.

It's kind of the same as why compression is being made instant: because it's a time sink that just gets in the way of the intended purpose of moving stuff around long distances with less hassle.

Thus rendering the idea of "local manufacture" meaningless.