More in the sense that we don't realize how spoiled we are (and how the standards have improved). I don't even have to leave this table to see the effects of share issuance or buybacks from a public company, and it's all updated in close to real time for me.
It's not that you couldn't make a _pretty-reasonable_ estimate, it's just that the ecosystem is much improved and easier to roll up for the indices we follow today. The Wilshire is from the 70s and the first flavor of the S&P came 30 years after the Dow (and was 'only' 90 firms). If you read Security Analysis (first edition: 1934) you can still see some of this in action; it mentions how only some statistical services (paid!) would calculate/estimate the current number of shares outstanding.
I don't know what is "updated in close to real time" for you, but normally companies disclose the number of shares outstanding and details about buybacks programs once per quarter.
It's not that you couldn't make a _pretty-reasonable_ estimate, it's just that the ecosystem is much improved and easier to roll up for the indices we follow today. The Wilshire is from the 70s and the first flavor of the S&P came 30 years after the Dow (and was 'only' 90 firms). If you read Security Analysis (first edition: 1934) you can still see some of this in action; it mentions how only some statistical services (paid!) would calculate/estimate the current number of shares outstanding.