a cab and amp is definitely the better bet. a decent head (again, Warwick are very good) and a cheap-shit 2x 15 cab will be plenty loud enough. And those Thunderbird basses are really nice. You should be able to get all of those quite easily within your budget if you go used. I'd still look into Yamaha basses though. I used to have a version of one
these years ago and I tend to think it was better than any bass I've owned since, some of which have been considerably more expensive. It's passive though, so you'll still need to upgrade if you want to use EMGs. If you're looking for something to last you indefinitely, Yamaha's build quality is about as good as anyone's and in its price bracket is pretty much untouchable. Although you'd need to be pretty reckless to destroy
any bass, regardless of who made it.