Generally prices are monitored in relation to other prices, perhaps adjusted for inflation or currency differences. This is less reflective of the change in values over time, because it ignores the time it costs one to acquire the means to acquire that value. As populations grow, it becomes easier to both produce most goods and to earn the means to acquire goods.

This comes from an article by Marian L. Tupy and Gale L. Pooley, based upon their research into Time Prices and the Simon-Eherlich wager:

In fact, that’s exactly what has happened to the affordability of 50 basic commodities between 1980 and 2018. Over those 38 years, the world’s population rose from 4.458 billion to 7.631 billion or 71.2 percent. Over the same time period, basic commodities, including energy, food, materials, and metals became 71.6 percent more affordable on average. For every one percent increase in population, in other words, resources became slightly more than one percent more abundant. Put differently, the time it took to earn enough money to buy one unit in that basket of 50 commodities in 1980 bought 3.62 units in 2018. The compounded growth rate of abundance came to 3.44 percent per annum. That means that the affordability of our basket of commodities doubled every 20.49 years. This relationship between population growth and resource abundance is deeply counterintuitive, yet it is no less true. The facts surprised us, and they will surprise you too.

This pertains both to abundant goods and to those considered scarce. The famous bet referenced in this article revolved around the price of five metals from 1980 to 1990. Despite a seemingly fixed supply, the price decreased in value by 36 percent.

Scarcity gets converted to abundance through the price system. The price system functions as long as the economy is based on property rights, the rule of law, and free exchange. In relatively free economies, therefore, resources do not get depleted in the way that Ehrlich feared they would. In fact, resources tend to become more abundant.

Time Prices have greatly reduced the true cost of acquiring most goods. As populations grow and resources are shared to a greater degree, it's reasonable to surmise the value of collaboration is increasing and that Time Prices may decrease at an even greater rate moving forward.