Why doesn't Caesar use the subjunctive consistently?

Question

In the Commentaries, Caesar writes:

Horum omnium fortissimi sunt Belgae, propterea quod a cultu atque humanitate provinciae longissime absunt, minimeque ad eos mercatores saepe commeant atque ea quae ad effeminandos animos pertinent important

So, I am guessing he is using the subjunctive with commeant because it is an explanation or reason for the primary thought, however, in that case shouldn't he also be using the subjunctive with importo and write "importent"? Instead he just uses the normal active "important", which does not seem to be parallel with commeant which is subjunctive.

Answer 1

The answer is perhaps surprisingly simple: they're all indicatives! Commeant is from commeare, which is of the first conjugation: the a is part of the present stem of the verb, so the a does not indicate a subjunctive. The imperative, for example, is commea.

The present indicative goes like this:

commeo, commeas, commeat

The present subjunctive:

commeem, commees, commeet

The imperfect indicative:

commeabam, commeabas, commeabat