Lately Nintendo had been avoided game with playable woman character.

I think they figured out that anything related to woman can give pretty big backlash there days so they had been hesitated to bring Samus back.

True, but fact remains Metroid still doesn’t bring in the same numbers as other franchises under Nintendo’s banner. Really this is more a “sad reality” of the gaming industry in general. For a non-Nintendo game: Mirror’s Edge took a long time to finally get a sequel. Also this isn’t the first time Metroid’s gone a long time without a new mainline entry, there was an eight year gap between Super Metroid in 1994 and Prime 1 and Fusion in 2002. F-Zero also hasn’t gotten a new entry in over a decade, and Kid Icarus was dormant for over 20 years until Uprising.

Some franchises just end up sitting on the backburner for a long time while the parent company chooses to instead put out guaranteed successes, and in time they bring back something old to see if it still has appeal. Maybe in a year or two we’ll hear something about a new mainline Metroid in the works, but for now all you can do is wait patiently, and frankly yes a good thing to do is still support Nintendo by buying other games from them you like so they can stay in business and hopefully one day make a new Metroid, because if someone’s such a spiteful fan that they hope Nintendo goes out of business all because of no new Metroid in a long while then that’s a misguided way of thinking.