Games are not made overnight unfortunately, but Mantle still has more games in development than DX11 did in its first year. That alone is encouraging. Let's see how many DX12 games are ready a few months after the API launches.
Not a criticism or anything was a decent read, though at least 3 of the questions he answered with 70 developers

It may have more games in its first year then dx11, you do have to remember that since 2009 (dx11) the pc gaming industry as a whole has grown monumentally. Some quick searches put steams user base at 25m in 2009 and over 80m to date.
More users, more demand, more money in the market, more interest from developers will give more games and more developer activity. If dx11 had launched in such a thriving market then who knows how many titles it would have hit in its first year.
