It's not because of the price of the game, this is fact. Just look at the trend with people leaving. "The game is getting boring" "I'd rather focus my time on IRL and other worthwhile endeavors, and so I quit entirely". 2 of the prominent ones. Look at Warcraft 3. I believe it's over a decade old and still has a larger playerbase than NW. Ask yourself why that is and you find the answer to both your questions. Warcraft 3 has a) a more in depth gameplay system and b) a larger esports scene. NW has tried to achieve a strong standing in both these spots but has ultimately failed, and will not likely happen. The game simply isn't advanced enough to keep it fresh forever. Sure there is many techniques but they are not as numerous as most other long standing games. You think of the games that have managed to captivate their community for ages and most of what you will come up with are strategy games. Warcraft 3, DotA, Starcraft: Brood War. Why strategy games? Because the amount of stuff to learn and discover, whether it be unit strategies, army strategies, map strategies so on and so forth is nearly limitless. In NW you master 2 (could be debated 3 weapons) and you're pretty much set for the whole game, and these weapons aren't particularly hard to master either. Learn to efficiently use the musket and bayonet and you have essentially mastered the game (Sword optional adding up to 3 weapons). In a strategy game if you want to be the best, be a masterful player or whatever you hope to acheive, you will have to master every single unit of every single army, on every single map, in which every single map any one unit has a different use and strategy and then tack on the fact that 2 of the 3 of these games have custom map creators which are commonly used and sometimes create entirely new games with whole new sets of units and strategies to master (Warcraft 3 ---> DotA) and you realize why these games have managed to keep their fans hooked for over a decade. The sooner you realize NW is not that advanced and never will be, the sooner you can learn to accept the game will die, and it is probably going to be soon. Not even the mods can make it fresh because it can be argued that maps don't have that big of an effect on gameplay (Not anywhere near as mucha s previously mentioned games anyways) and most mods are a reskin not a total conversion, so there is not much change. Honestly the big secret to keeping the game alive is the modders, more specifically, we need an exceptionally talented and creative mod team to make something that makes the game different enough for you to believe it is an actual mod/ total conversion rather than a reskin. The game needs to not only look different, but feel different. Keep the same old combat that we've grown to love, but implement it in a way that is new and fresh. cRPG team has managed to do this for Native, as has the crew behind Vikingr. We've yet to come even close to this for NW however, I'd say the closest attempt was IE but they messed up on 2 areas 1) The talent was not there (Sorry but it's true, the servers barely handled most of the big things people were excited about like grenades and artillery, and it became unplayable with 100+ people), they had too much ambition and maybe should have tried something more tame for their first mod. and 2) It focused on gunplay rather than melee. Only a daft man believes gunplay is what keeps people hooked to NW for 2,000+ hours. No, huge 200 man organized linebattle events and in-depth melee keeps people hooked for thousands upon thousands of hours.
I'd like you guys to look at Native. We know Native has the larger playerbase at this point and time, now you have to realize why. The answer is simple, there is more weapons to learn and more combat styles to have. The large selection of weapons and weapon types along with the customizability makes the game much more in-depth than NW. Simple as that. Now look at it's most successful mods and see what they do. cRPG, Nord Invasion, PW. What do they have in common? They take the core strength of Warband and revolutionize it with a whole new system, implementing it into something new and fresh that veterans will be familiar with, but new to at the same time, and to newcomers will feel like a whole new game. cRPG adds a persistent role playing system to the game, making you work for your gear and stats, rather than having them handed to you at troop selection, and it also freshens up and improves combat with many new systems and rebalances. Nord Invasion turns the game into a coop wave survival mod with the persistence of cRPG. PW takes the combat of native and adds it into basically a whole new game where you undergo the role of whoever you want to be, whether it be merchant, miner or town guard.
Mount and Musket did the same thing as these mods, it took the core concept and turned it into basically a brand new game. Adding muskets and the resources for players to run organized linebattle re-enactments? Yeah that's minty fresh. Unfortunately the concept is just not as advanced or changed to have the longevity these other mods have. If we want to breathe new life into NW we need to update the formula to where it keeps the core concept but feels like a new game. We need a MRPG (Musket Role Playing Game), we need a PLB??? (Persistent Linebattle) (It's a thought), something that will reinvent the game but keep the things we love. That's what the successful Native mods do. You can't say Native isn't made more popular and kept alive by it's mods, without them it would be dead already. Unfortunately, thus far, NW has only been kept alive by itself. All it's mods so far have been re-skins or failed attempts, and it will stay that way until we get that one mod that gets it right.