A lot of what you type is based in reality so I presume youve done a lot of reading on it. Willpower is a finite resource: if you have to expend a lot of delayed gratification in one are a of your life you have to be mindful of other areas that require willpower as you will be more prone to failure. As you stated it's hard to gauge how you are feeling in respect to how you felt a week, month, years ago and its hard to accurately gauge whether burnout is approaching.

You should do more reading on the matter. I think there would be a fairly good framework somewhere that could be boiled into a few variables for your game. I doubt you'd have to come up with anything groundbreaking, read a couple books on willpower, addiction (will verse you in what happens when motivation goes awry) and the like.

Some general things I think may prove useful:

• A key to happiness is having intrinsic motivation. This goes against your motivations. If a person does things purely because they want to, for themselves, even if you fail, you will probably have more resolve to keep going. As opposed to more extrinsic motivation like having others compliment you for your success. Being the former is definitely more conductive for happiness and probably reducing burnout risk too.
• Look up how compromised decision making (and ultimately willpower) is when sleep deprived, hungry, stressed, and generally bothered by something. Its huge.
• Goals must be actionable, realistic (SMART), and achievable in small increments
• People need time off to recouperate. For instance I believe I read something that said humans need to write and defragment their thoughts for like an hour a day because we process so much information welose track on whats important. We intake and process data all day long and seldom spend time pany of it and thinking and untangling it all
• I woud probablylook into the 80/20 rule thats a neat catch all phenomenon that applies to many things in life. For example 80% of the most productive work results from 20% of your time working. This can be applied by thinking about diminishing returns. Eventually its time to call it a day and relax knowing that you are risking future burnout for lowered productivity. For example boxing off allocated times or even days where its strictly no work to unwind.
• Look up supernatural stimuli. Its not just crack cocaine and heroin that is making people ruined in terms of discipline and motivation and willpower. Sugar, social media, porn, games, drugs, alcohol, junk food, iphones. Its all stimuli we didnt evolve to handle and sustained overuse ruins your brain chemistry making it harder to stay motivated in day to day life.

My main takeaway is you should probably have an intrinsic/extrinsic motivation variable in your game. See it this way, if you are extrinsically motivated (money, status), you may rally to slog on but it may be at the expense of internal happiness. If you set out to do something because you simply enjoy it, want to thrive and such, you may be happier, but it might not make you pursue a high money, high pressure job. Extrinsically motivated people may be more successful materially but you never 'get there'. Youre always chasing the dragon, its fleeting as you say. So there is probably an internal/external tradeoff to beinputting into your game. Perhaps it can even calculate how internally/externally motivated you are through several variables. And the tradeoffs will be apparent. (money/status vs self actualization/contentness). Read a book on drugaddiction andhow it impacts decision making to get a good grasp on how willpower can fluctuate and include that. Supernatural stimuli and the such will would have negative impact on longterm sustained work and tenacity. Lack of self defragmenting through journalling, positive affirmations, talking therapy, mentoring and such would have a negative impact on self actualization / internal motivation

Another variable I would look into is 'LOVE'. And not meaning a partner. Love broadly speaking would mean acceptance and valued in community, a number of friends who are lifelong friends who you trust to confide with and speak freely without fear of consequence (like family), strength of connections with others. Remember that humans are social creatures and its the cornerstone of life. It definitely has its place in your game. Social isolation makes people mentally ill. Look up how solitary confinement changes the brain. A lot of people live to that level of social depravity despite not being in prison.

Hope this helps

Ah right then ,bet shes crying over her billion dollar franchise. she must be living on a straw bed by now, bless her. You cant be a 1 hit wonder if you write 7 smash hits in a row that basically represents one of the grandest literary works ever wrote, my dear.

Celebrities weren't forced upon us human worship is innate to humans. The onus isnt on the consumer to stop worshipping them since its a natural human drive, if you want celebrities to go away you'd have to remove the incentive for them to exist or to ban their existence through legislation.