Your poll is in error, you only have 2 of 3 possible options. Also this issue has been brought up before and the only data to truly confirm or deny it is private to the stakeholders.

A better poll would have 5 options, rapidly growing, slowly growing, holding steady, slowly declining, rapidly declining. However you would only get skewed data as it only surveys the hard core fans that make the effort to go to a website and register for a forum and not a true data set like the game devs have so ultimately only would provide confirmation bias of your theory but no factual information.

I think the game is slowly growing but has a high churn rate due to the game pace that the average person isn't looking for. It is also lacking a group/alliance ladder system to feed more of the competitive minded player. It is to the point where if you have a well organized team of 5 you can almost certainly win a round just by working together in coordination (the 5 do actually have to know what they are doing and be active*) but rarely to I encounter teams as organized as ours and have found myself running less rounds simply because it feels like rinse and repeat.

Speedchef put it perfectly. I think new players are rising constantly just from filling all the maps however keeping people active and engaged during the map's round is tough. More and more inactive players in each round I'm in that are taken over by the AI. RTS is a dying breed sorry to say. We are seeing it all over multiple gaming platforms. Younger kids want fast action like Fortnite.

It was never really a popular game

There is no evidence to say that the game is declining.

Ah, but you do not say the likewise which is that there is no evidence to say that it is growing.

According to me the game is near the not growing, not declining mark. According to my experience new players and generation don't like slow games like this and if they want a fast game like this they would instead go for HOI4 as the *2 speed and other maps don't make the game from going on for weeks to going on for couple of days, it makes the time taken to do things shorter. The game is also mind using, and when I show my friends and brothers this game, they sat 1)it is too slow. 2) it is strategic and uses the mind, and they play games for fun, not to use their brains extensively like they do in studies. Thus because of the above two reasons the game will only grow slowly as their are exceptions like I am, who likes only grand strategy games.
It will also not decline as older players who have played for years/ months, are mostly not leaving as playing so many games they start to love/like the game. However it is slowly declining and I voted declining as even old players like me who have played for years are leaving as, the game had only one major 1.5 update. Other minor updates under the 1 and 1.5 version, didn't change much in the game and how it was played. Thus if you count there was only one major 1.5 update, which has now became old.

Here's an example - In the 1 version my plan was always, pick any costal nation, make an equally powerful navy, air force, and land army, made of all units equally spread so that they were diverse and could take down anyone with there diversity.

And, In the 1.5 version, I classify it as major as it changes my, and all players game plan completely.
The new plan was, choose Germany(As it has the most neighboring AI countries-8), Make equally powerful navy, air force and army, In navy only make submarines, In air force make fighters and attack bombers, and anything else if needed, and in army only make Motorized Infantry, SP Artillery, SP AA, Heavy Tanks.
Thus this was the only major updates making me from any nation, any unit player, to Germany and some unit player.

Thus the game needs some major updates like this or else it will slowly decline for now (as now old players are leaving as some of them have seen all aspects of the game and are bored like me), and if a major update doesn't come it will decline rapidly in some time (as more players leave).
For ideas check the suggestions and have many suggestions being added at once.

i disagree
with the last update the game has lost its identity, many now see this game as merely a cheap copy of CON
the veteran players are leaving en masse because of this
hence, with the lack of the veteran playerbase, yes, it is in rapid decline

I was always dissatisfied that actual strategies in battle aren't useful in Call of war. For example, encirclement was a big part of World War II. Most troops would surrender in be killed when surrounded. However, encircling in call of war has no effect what so ever on troops. I believe that this feature should be added to call of war.

I think so that the devs should try to do updates what the player base says.
Like- Supply Lines, Field Hospitals, Unit disbandment, Unit Veterancy etc.

No one has any proof of what has been saying above happening except for the game developers.

Once again, every gaming community that has a forum has a thread or maybe several saying "this game is dying/declining" whatever. Go on any game's community forum and I will promise you that there will be a post saying this. For there is always someone out there negative enough to discuss problems because it's easier than offering solutions.

with the updates, the very foundation of COW is being eroded, people stopped seeing an unique title, they see this as a cheap copy of CON
some of the things in 1.5 that are highly rejected by the most commited players, just to give a few
the removal of SBDE
bad resource dispersion
the speed of the research tree and unit building
inability to build units in rural provinces
and there is more...

COW had a golden age but it ended around 5 months ago. Now its all downhill from here. Removal of 1.0 will mark beggining of the end for this game. mark my words

You hate 1.5 so much?

CoW's golden age is going on as there is 100's of new players every day.

It is advertising in many areas. It came as an ad on the national news

In the play store there is 10 million plus downloads yet most people play on the browser!

National news?