Can all data be represented tabularly?
One way or another any data can be represented in a table or even in a big binary string, since after all the physical memory of a computer is just one big binary sequence. But the question is whether the table format adequately represents the semantics of any data, and the answer is definitely no: while there are tabular representations for graphs, text, images or videos, these representations simplify and/or make assumptions about the nature of the data. Virtually any representation is a simplification of the data it represents, but some representations are more faithful to the original data than others.