Stock profiles are distributed by paper manufacturers free of charge, and more than often are not readily available for all printer models. If they are available, they are often of less than wonderful quality.
People seem to get frustrated by this, thinking that it should be in the paper makers own interests to supply profiles for all printer models as these profiles help people produce gorgeous prints. However, it's not as simple as it first looks.
Custom printer profiles provide the best results as they are a description of your printer’s behaviour with respect to colour on your particular media – you simply can’t get any better.
Profile making companies, much like software companies in general, do not sell you profiles as such. They sell you a license to use the product of their software, which in this case is an ICC profile, in limited circumstances. These licenses preclude the further distribution of profiles, and indeed are particularly clear on the issue of public distribution - this is a serious violation of their licensing terms.
These companies take this very seriously and have apparently sued several companies and individuals for violating these terms. This is why we can't make available our vast library of profiles. The license for our system allows us to make profiles specifically under contract on a one to one (or company to company) basis, but not to further distribute these profiles in any way.
Companies can buy licenses to distribute profiles, and clearly, there's some room for negotiation and the bigger manufacturers have made deals. The reality is though, that for most companies the costs are simply prohibitive. So they either limit the number of printers they support, or use lesser systems to produce the profiles.
The end result unfortunately is to offer only a small selection of printer models that do not cover all consumers’ devices. Funnily enough there is at least one quite good open source system available, and it's an ongoing surprise that more paper manufacturers don't use it.
Profiles are also quite difficult to properly support. They're easy to use when you know how, but over 10 years of making thousands of them, it's become clear that a lot of people simply don't have the IT skills to use them properly, or don't have the time or inclination to learn how to use soft proofing properly. For a company like, for instance, Epson, with multi-national support commitments and systems, it becomes a significant logistical problem to offer these and then support them.
It's not the sort of thing that 'by-rote' support people reading from pre-scripted sheets can handle. It takes highly skilled and experienced people to support profiles properly as computer systems and printer drivers are very much moving targets. Many paper companies are now, if anything, moving away from supplying profiles.
All that being said - the best results always come from custom profiles. Stock profiles are not made for your printer and do not account for the significant unit to unit variance inkjet printers exhibit. So while they are often marginally better than no profile, they're usually a long way off best possible quality.
Custom printer profiles provide the best results as they are a description of your printer’s behaviour with respect to colour on your particular media – you simply can’t get any better. At ~ $60, relative to the price of quality papers, a custom profile is well and truly worth it. Not using them is simply false economy as any person serious about high quality printing learns in the long run.
And it's worth remembering - the vast bulk of people that use papers without profiles, and most won't even have heard of profiles. Papers are generally designed to produce decent results out of the box with obvious settings - e.g. all semi-gloss papers will generally print ok if you set Epson Premium Semi Gloss as the paper type in your driver. Profiles are all about moving beyond 'just ok' to 'really spot on' - and that's what custom profiles are all about.