If they don't shorten the time to top age somehow, there won't be enough players in cold war to justify releasing a space age. The big spenders and early adopters will be playing on their own. Cold war hitting down to global was an acknowledgement that that is the last age with a wide enough player base for real gameplay.
There is a normal cycle for lots of products - early adopters spend the most, get all the glitches and issues, and are usually happy to be out in front. Then the bugs get worked out, the cost comes down, and everyone can get on board. The early adopters can keep buying the newest stuff for top dollar, but that doesn't mean the older things they paid for should stay as expensive as the day they bought them. The argument that times can't be shortened because the early adopters spent more doesn't match anything else in the real world.
Nexon has to find a way to grow their player base again if they want the game to continue. My opinion is that means they need to get brand new players to a point where they can participate in the top levels of the game in a reasonably short period of time. A max offense, decent defense global age base in 3 months without spending or excessive grinding for instance, with the ability to move up and be a weak atomic. When they release space age, adjust older times so the same thing is true for atomic.
That might tempt a lot more people to spend than the current condition. Get them hooked, let them see what the game is like where the active players are, and then maybe they will spend to move up to cold war. As it is now, a common thread on the dominations reddit is - I am in iron / classical / medieval age and NEVER have been attacked, does anyone play this game? No one should have to play for months before being attacked, if there are hardly any active bases down there compared to the abandoned ones, let people skip to the active ages very quickly.