That's certainly an option that you can setup with your lab.
Depends on the lab of course. So many just “demand” sRGB, or have no current profiles or can’t keep multiple machines behaving the same.
The problems that I've witnessed with that type of approach is that labs change papers and update profiles and customers are still using the old profiles.
Agreed but this is solely the lab’s fault here. Its not rocket science to send out an email blast or update a web page with a newer profile. We could ask why the lab can’t keep the process in line so that the original profiles remain valid.
Noritsu profiles that have the RGB GCR alteration can't be used in Photoshop so color fringing in the shadows could be present. And embedding a large output profile in each and every image can slow down the process of sending files electronically.
Can’t comment on the first part but I’ll accept this as being an issue. The 2nd bit seems pretty silly considering the size of most images and the size of most RGB output profiles. Sure, for customers with dial up, its a problem. Its akin to demanding every file sent be a JPEG and a large compression instead of a lower one (or a TIFF).
For most professionals, being able to work in their working space of choice while soft proofing with the labs profile, and sending their working space images to the lab for printing works really, really well. But naturally there's room for other workflows as long as one has a thorough conversation with the lab.
It might work really well but we don’t know if it can work far better. The bottom line is, this industry by and large is far less concerned with best practices in terms of soft proofing, conversions and consistency (although there are obvious exceptions who deserve the consumers dollars). Is it any wonder that more and more photographers are handling the output tasks themselves in house using Ink Jets when the production allows?