Here is the situation as I see it: I have over 30 years experience in marketing strategy. When you have a brand with declining new users and a drop off in retention of the new users you are generating, cost management become a priority and a potential end game strategy for the brand's demise is implemented (hence the virtual elimination of any new developments for the game). You might make some simple, low cost cosmetic changes to your product periodically, giving it the illusion of attention. You would also assess your customer base and eliminate elements that would cost you their business (i.e. firings)
If you have concluded that the long term prognosis for the brand is not good but the erosion of your customer base is gradual, you would maximize your profitability by being austere about spending money and manpower on the brand and ride out its decline for as long as the brand creates any profit under its own power. Your attention would be focused on any other brands that have growth potential or the development of new brands.
How many of us have said we will continue to play even if we don't see activity on the part of management? They know that and take that into account. If management had not concluded the HD brand is terminal, we'd see regular information exchange between vendor and customer (e-newsletters, status announcements, updated user guides) with a focus on customer satisfaction elements.
Enjoy HD for as long as you can but do not anticipate change.