Shouldn't this も be が?

Question

This sentence is in my JLPT practise book in a section on the use of 目{め}まぐるしい:

社会{しゃかい}の目{め}まぐるしい変化{へんか}についていけず、時代{じだい}遅{おく}れになる会社{かいしゃ}も多{おお}い。

I think the sentence is saying, "There are lots of companies that do not keep up with the bewildering changes in society."

If that's right, why does it use 会社{かいしゃ}も多{おお}い instead of 会社{かいしゃ}が多{おお}い?

Answer 1

The も suggests that there are (possibly a lot or more) companies that keep up with society's changes, but there are also those that don't.

が　is also possible here, in which case the meaning would have no reference to companies that keep up with the changes. It doesn't change the overall meaning, but does change the scope of what the speaker is referencing. With the も example I might expect more that the speaker refers to both groups of companies in subsequent sentences.