The reason why so many launch a funding campaigne is, that its very expensive to print a high quality deck with custom prints. If you want a high quality custom deck, the company has to make custom printing plates first. They are big (for sheets) and made of good materials and are likely to be thrown away after your deck is printed (or remodeled wich is also expensive). Those are only realisticly payable if you sell a whole bunch of those decks. I bet there are companys out there who will print single custom decks but they, most likely, wont have crushed stock and air cushion finish. So its always a investment for the company to make new printing plates, and they will only do it if they get the money for those effords.
If you have an interesting deck Idea…. present it! Get into Photoshop or GIMP and flesh out your Idea. If you dont have any graphic skills, ask a friend to do it (or a forum like this). There were decks that looked terrible but were fully funded, so it cant hurt to share your Idea. Card collecting people are soooo eager for new decks 😉 When you´ve done that, I´d reach out to people who got their decks funded and ask how they did it.
Also card ppl, please call me out if Im talking bullshit, I pretty much just read two articles on the topic and have no experience in making new decks <3