Axell was Dragonstone’s castellan for about 10 years or do you mean just that as Lord, Stannis could only count on 3000 men from his recently pro-Targaryen vassals?

The latter. I’m saying, when Stannis can only call upon the Lords who owe their allegiance to Dragonstone, he’s more dependent on his in-laws for manpower than he is after Storm’s End or after he has his turnaround on lords (to be lordly is to be false, we’ll make new lords) with Davos.