CEO John Hanke of Niantic was interviewed by Andrew Webster of The Verge to celebrate the 1 year anniversary of Pokémon Go. One of the topics discussed in the interview was the development timeline of the game and John Hanke confirmed they are behind their own internal schedule for the game. He also discussed that trading and player-versus-player combat are still being worked on. John also explained that development has been hampered because of a lack of money and is quoted: "But we only had so much money, and we were doing what we thought was reasonable."

Interview Question - When you look at where the game is now, and compare it to your initial road map, how similar are the two?

We lost probably six months on our schedule because of the success of the game. Really all the way through November and December, from launch onward we were rebuilding and rewiring infrastructure just to keep the game running at the scale that we were running at. We were fortunate to have a massive launch, a massive success, and many, many more users than we had planned for. But we had to redirect a substantial portion of the engineering team to [work on] infrastructure versus new features. That switched off things like extending gyms, it pushed out things we still want to have, like player-versus-player and trading. I’d say we’re about six months behind where we thought we would be.

Source: https://www.theverge.com/2017/7/6/15911936/pokemon-go-niantic-john-hanke-interview-one-year-anniversary