You're blaming a lot of normal ETL problems on DSVs.
Like, specifying date as a type for a field in JSON isn't going to ensure that people format it correctly and uniformly. You still have parsing issues, except now you're duplicating the ignored schema for every data point. The benefit you get for all of that overhead is more useful for network issues than ensuring a file is well formed before sending it. The people who send garbage will be more likely to send garbage when the format isn't tabular.
There are types and there is a spec WHEN YOU DEFINE IT.
You define a spec. You deal with garbage that doesn't match the spec. You adjust your tools if the garbage-sending account is big. You warn or fire them if they're small. You shit-talk the garbage senders after hours to blow off steam. That's what ETL is.
DSVs aren't the problem. Or maybe they are for you because you're unable to address problems in your process, so you need a heavy unreadable format that enforces things that could be handled elsewhere.
I would kind of disagree.
We are talking here in the context of scientific datasets. Of course ETL plays a part here. However here it is really more the interplay of Excel with CSV which is often outputted by scientific instruments or scientific assistants.
You get your raw sensor data as a csv, just want to take a look in excel, it understandably mangles the data in attempt to infer column types, because of course it does, its's CSV! Then you mistakenly hit save and boom, all your data on disk is now an unrecoverable mangled mess.
Of course this is also the fault of not having good clean data practices, but with CSV and Excel it is just so, so easy to hold it wrong, simply because there is no right.
> so you need a heavy unreadable format
I prefer human unreadable if it means I get machine readable without any guesswork.