This copied the superficial data layout without the key benefit of modern columnar formats: segment elimination.

Most such formats support efficient querying by skipping the disk read step entirely when a chunk of data is not relevant to a query. This is done by splitting the data into segments of about 100K rows, and then calculating the min/max range for each column. That is stored separately in a header or small metadata file. This allows huge chunks of the data to be entirely skipped if it falls out of range of some query predicate.

PS: the same compression ratio advantages could be achieved by compressing columns stored as JSON arrays, but such a format could encode all Unicode characters and has a readily available decoder in all mainstream programming languages.