I think anybody investing (very seriously) in pro-level giclée (not desktop printers)
Sorry, but the main differentiators between the massive pro-level printers you seem to focus on and the desktop printers you seem to not take seriously are not necessarily in the domain of print quality. Which is to say that there are plenty of 'prosumer' desktop-sized inkjet printers currently on the market that deliver the kind if print quality you seem to exclusively associate with 'pro labs'.
For larger systems, there are a few rationales that justify their bulk and the larger investment in equipment:
* Ability to print larger media
* Ability to print on other media except paper (also large; think door/wall panels etc. and other display media)
* Productivity; i.e. square meters of print/hour
This is for the graphic arts segment; if you include production printing for e.g. mass marketing, print-on-demand books etc. it's especially about productivity and per-surface-unit economy, as well as integration into a larger chain of pre- and post-processing that takes a print job (typically not a single image) and results in a bound & glued book, folded flyer etc.
You mentioned energy and that's really only a significant factor in the areas that are NOT about typical photo reproduction as we discuss it on this forum; we see high energy costs in super-fast machines that pump out hundreds of sheets per hours for e.g. on-demand book printing; part of that tech is still laser-based btw, which inherently has a higher energy profile. But high-productivity (non-graphic arts) inkjet also involves dryers to rapidly pull all water out of the paper. And then there's the category of UV gelling inks that involve powerful UV lights to harden the ink immediately after it's deposited. None of this relates to high-end photo printing, which is a relatively low-energy endeavor. For a photo lab that prints inkjet, the main energy cost is in heating or cooling the building so the people working there are happy; not the printers as such.
The technology that's needed to create stellar photographic prints is precisely the technology that is also packaged in higher-end desktop printers; it's really not exclusive to roll-fed wide format printers that you may be used to seeing in your local 'lab'. This technology revolves around (1) ink delivery; i.e. the head and associated motion control to control droplet size + placement, which together determine effective resolving power and (2) the ink system itself, i.e. the pigment dispersion in a watery carrier with all the adjuvants to make it work reliably.
Where you do have a point for sure is that if you buy a desktop/consumer level inkjet printer, you will typically pay a bit more on a per-liter basis for the inks, but don't make the mistake of thinking that a pro lab pays so much less as ink is the manufacturer's revenue model also for that segment. In terms of media, buying in bulk also can make some difference. But the major factor is the question of volume and investment in equipment; if you only print 100 photos per year, your $1k printer will cost $1/print in just investment before you'll dump/replace it. Delegating your printing to a lab can be for this reason
Having a lab print can also have to do with technical expertise; on that part we agree - a good lab will guide you as a photographer through the process and save you form having to deal with all the technical intricacies of making a good print; they'll just present you with some choices that make sense to you, usually with some draft prints to illustrate, and you get to pick the direction you want to take it in. This is really the main differentiator - as a home printer, you either have to be happy with what the machine spits out 'out of the box' (which actually is darn good most of the time today) or you have to invest some time into understanding how color management works and experimenting with different media to get what you want. That takes time, and it's time you can save by paying a lab for their efforts. There can be economy there, but it depends on what you print, for what purpose and how much of it.
The production factors story is a whole different ballgame and your post mixes up several segments of inkjet printing - which may indeed be performed together at the lab you're using, but the part that you use, i.e. high-end photo reproduction, is precisely the segment that is also available in a desktop package. And yes, it's really the same (or higher!) quality, durability etc.
