Short answer is YES. Not all transactions are the same.
Using an analogy, which is not perfect but close enough, consider the Excel spreadsheet as a further example of distributed blockchain, on continuum from BTC to STEEM to Excel. BTC has close to perfect security proven over years, STEEM in the middle, and Excel at the far end.
There are billions of transactions in Excel spreadsheets every year. But is the Excel spreadsheet technology valued at $100 Billion? No? Why not? Because not every transaction in an Excel spreadsheet carries value or is linked to value. Many are just meaningless text.
Making all the Excel spreadsheets in the world somewhat similar to STEEM. Most of the "transactions" are meaningless text. So it is hard to ascribe value to that.
Until the "transactions" are linked to value, it is hard to ascribe value.
Why do FB and Google have such a high market cap? Is their market cap driven by the volume of posts or searches?
Sort of but not directly. Their value is driven by linkage to advertising, which is linking to a money stream.
Until STEEM can make some sort of comparable linkage to some money stream, STEEM is just an interesting play toy.
Are their money streams STEEM could get linked to? Sure. Quite a few possibilities exist.
But until their is a linkage to some money stream, then the "transactions" on STEEM are perhaps technically interesting but of much less financial interest.