why aren't there more train packages/discounts available? We have loved traveling by train - but its pricey!

We have taken three trips by train - overnighters in first class - they have been a blast - but, its very difficult - even impossible - to find packages or deals for the train like you can for plane, hotel, car, etc.

I completely agree.
There is no competition, and no insistence that Amtrak executives are accountable for their budgets.

you really need to speak to a rail adviser at any manned station they will be able to tell of a great many offers and discounts for rail journey . A tip for you buy the relevant discount card and then plan your journey six weeks before hand if possible. this will give you the best chance to pick up the offers as they don't show on the system before this and are snapped up very quickly once they are out
good luck and happy travelling