"Nobody needs a big dog" - nobody NEEDS any sized dog if you want to talk about needs?
"I have a nervous yappy dog" - well I hate to say it, but what training and socialising have you done in order to prevent them turning into a nervous yappy dog?
Big dog or small dog, it's a lack of training and responsibility that causes the issues, not the size of the dog.
As a child I was randomly attacked by a Rottweiler. As an adult, I've been randomly attacked by a Jack Russell, and randomly attacked by a Yorkshire Terrier 🤷♀️
If you look into the history of certain breeds, most of them were bred for certain jobs.
Dog owners, prior to owning a dog, should put in every ounce of effort they have in researching breeds, and the temperaments and behaviours that come with each breed. The responsibility lies with them.
Prime example is when you get a low active family that go and buy a highly active dog, (regardless of size), they don't walk it enough and then complain that it's destroying their house, that's their fault for not meeting the physical needs of the dog.
Some dogs have a higher prey drive than others, and feel the need to 'chase' something, this can be satisfied by playing fetch, or using the dog as a working dog in the industry or was bred for (Jack Russell's for example, very common and a lot of people buy them as a lap dog, but originally they were bred as ratting dogs, and chances are if they ever came across a small animal or rat, they would not only chase it - but they would kill it too)
Then there are breeds that were bred simply for guarding, some of them bred centuries ago to guard vineyards and other expensive things. so they are territorial at home, bark a lot when visitors arrive, but are super soft to interact with. And a lot of them have very low activity levels, as their purpose to be bred originally was not to be active - but to wait around for an intruder.
People need to seriously start weighing up their lifestyle, and which breed would fit that lifestyle. For all sizes.