The modern, pre-computerized machines have one big failing as I see them, plastic.
There are many plactic components which are much cheaper, easier and faster to make. It is also quicker to get into production with the plastics than having to work out machining on metal parts. But, plastic parts are also designed to fail. Plastics have a limited useful life under stress. Certain lubricants cause problems. Proper lubrication will only do so much to keep the plastics going. When the supply of repair parts is depleted, there are no more unless you can have a good part 3D scanned and reproduced by 3D printing or know a machinist who can make you the part out of metal.
Many manufacturers dispose of their replacement part inventories after a certain amount of time. When this happens, even the pieces that are still there and useful are gone. Old machines were made simply so that a needed part could be made by any competent machinist. Many of the plastic gears, cams and other parts would be very hard for anyone but an absolute master machinist to reproduce. This was the beginnings of designed obsolescence. We, as a population, said nothing about the quality problems and issues with repair, usually because of a lower price. So, it became the way of manufacturing. Now everything is designed to last a certain amount of time and disintegrate. Sad state of affairs really when you think about it.