Its not even just the money issue. There are likely technical limitations involved. I remember an interview about Dragon Age Inquisition I think and the developers mentioned there were things like a limit to how long each piece of voice over could be so lines had to be kept to a 'twitter' like limit and also limits to how much dialogue could be loaded into memory at one time. And voice files are some of the largest files soaking up hard drive space. Plus if 9 people have already recorded a line, and you later decide it should be changed . . . well lets just say it greatly restricts your options.
uh... soundfiles are actually quite small compared to everything else in a game (unless you go for raw uncompressed PCM which I wouldn't know why you would). Also, limiting changing dialogue later restricting options? isn't that already a problem for all the voiced NPCs? (granted, maybe not quite as much) they should just go for no voiceacting at all then.
I also keep seeing people mentioning how expensive it is - it's not like they are using Hollywood talent, an average voiceactor makes ~$200 an hour. For the money spent on a CGI movie like the intro (now THOSE are expensive), you could get a ton of voiceacting.
