Dish's offer is free HD for "life".
....to new subscribers who commit to 24 months and the automated bill pay.
The strategy there must have been:
1) Locked in revenue for new subscribers (only)
2) Reduced churn rate for that batch of new customers
3) Reduced collections due to automated bill pay
4) One time new account acquisition hit for accounting purposes
5) Many of the new customers will be cable defectors, based on the cost comparisons
Seeing all those upside considerations, DirecTV appeared to have jumped on matching those things quickly for the same reasons.