There are certain technologies from the 19th and 20th centuries, and even some from earlier, which cannot be further optimized. You can refine them for more specific applications, but you cannot improve them, without taking away their optimization in some other way: 'a thing is perfect when there is nothing more you can take away.'
Take the case of the 'safety razor'. You can imagine that this made the lives of men, and women, much easier than when they had either to use a straight razor, visit a barber, or do something more creative for hair other than on the face. A straight razor in the hands of a skilled barber does give a superlative shave, but this technology gives one nearly as good in the hands of a duffer. All of the double, triple and absurdly quintuple, blades neither improve the shave nor the safety. Even if they improve the shave for you, the disadvantages for most people are telling: they are ten or more times as expensive per shave, they are wasteful of materials and packaging, they are not interchangeable, and they gum up and wear out quickly. The best and cheapest home shave is a 'safety razor' and a good shaving soap: brush not required, hot water or cold as an option. Shaving foams are another 'innovation' that is no such thing.
These are just a few I can think of from the top of my head. There must be many more (leather bike saddles!).