Yes, ease of use and time are a big problem, as is strength and costs, both are issues on production based 3d printers as well, so don;t go thinking the big ones are better.
No, what many forget is that many people simply don't create much.
You can buy a small personal machine shop for your garage for about the price of a small 3d printer, you can also put together a nice woodshop as well. You can also buy tools to fix your car, or professional grade photo/video editors for photo and video editing. So why doesn't everyone have these? They have no need or want of them.
The only reason printers in the home took off because people found a use for them, or got them free with their computer. Kids could type and print reports for school, you could print off reports for work, etc... What purpose does the average person have for modern 3d printers? NONE. It doesn't matter if the price is $30, it's time consuming, fickle, technical, and expensive. Do you rally want to spend 8 hours, and $10 on plastic to make a vase you can buy at Walmart for $3. Of course not.
It doesn't matter how simple you make it, or how cheap, so long as it's easier and cheaper to just go buy the item you can print, it will never be on the kitchen counter. Get us somewhere close to Star Trek level replicators and yes, then we may see it, but until we get anywhere close to that, it's simply not going to happen in the average home. At the moment hobbyists and professionals are using them because they either need them or want to play with them, but the average home has absolutely zero use for one, anyone who says otherwise is riding the hype train and probably trying make a buck from it. Current 3d printers belong in labs, machine, hobby and fabrication shops, not the kitchen counter and it will remain that way for a long time yet.