It’s not that you can’t model data that way (or indeed with structs of arrays), it’s just that the user experience starts to suck. You might want a dataset bigger than RAM, or that you can transparently back by the filesystem, RAM or VRAM. You might want to efficiently index and query the data. You might want to dynamically join and project the data with other arrays of structs. You might want to know when you’re multiplying data of the wrong shapes together. You might want really excellent reflection support. All of this is obviously possible in current languages because that’s where it happens, but it could definitely be easier and feel more of a first class citizen.