The total supply doesn't really matter, what matters is how much the team holds and what the price of the token is. Tron, for example, is a coin with a very large total supply and it grows strongly because the team holds a lot of coins, has an actual roadmap and can accomplish a lot of big goals. Therefore, the whitepaper is still very important, we should observe the team's strategy to protect the price of coins more.
I can't agree with you, total supply matters! Supply and demand have an important relationship that determines the prices of most goods and services. Tron, ripple, and some other coins have a large supply, to ensure people that they will not just dump those coins usually in wp is stated that coins will be locked for certain time, and for what those coins can be used.
It's tricky, it's on us to believe that those coins will remain locked for a specific time period, we can believe that those coins will be used for developing, we can believe, but that is not the truth necessarily.