I suspect they are 100% self-funded and work in cyclical R&D and production runs, rather than doing things simultaneously. When they release a new console, they seem to emphasize profit margin and go for 100% sell-through. Warehouse fees are a significant burden on small businesses and can really eat into profits, so I'm thinking that's the motivation there. It also means their production schedule is very predictable, another big plus for a small business. Then they just roll into R&D until they run out of money, prompting a new product preorder or another run of an old project.
Or they're just bad at business and/or have production problems.