It is very simple why this is not a good policy.
Let's say you are a software engineer working on some software product/service. You are working hard on that software, adding features, fixing issues, maintaining it, etc. The buyer pays you $100 today for that software.
Tomorrow you release a new version, with lots of upgrades and new capabilities. The buyer for this software says "my money should be worth more tomorrow than it is today" so they offer only $80 for the new version. Boom -- your work is worth less every day!