My neighbour has two dogs that bark in the garden for hours on end every day. They are outside in the garden yapping from 6am until 8.30amish, when they go to work. They get home some time mid afternoon, and yapping resumes intermittently from about 4pm until about midnight. Nobody calls them in during this time.
I've tolerated this for years (the dogs have to be very old now, and they have always done it) but more recently it gets on my nerves because they're out there at stupid o'clock. I'm much more aware of the sound as I struggle with sensory overload.
We live in a small neighbourhood, everyone knows these people and everyone loves them, so if I were to say something it's likely all of my neighbours would them hate me. Most people have dogs and all of them bark a little bit (including mine, the difference is if she does it in the garden then I call her inside immediately - mostly she barks in response to the barking dog chorus, which is triggered in the evenings by these yappers) but these ones just take the biscuit.
RSPCA won't care because the dogs are looked after generally, they just have unsupervised garden access and bark all day. I do feel very sorry for the dogs to be that sensitive to the world around them, but the owners aren't phased by the barking.
YANBU - you should say something
YABU - ride it out like you have for several years and wear ear plugs all day