This is the same as saying "It's not fair to rise the price of coffee, because it costed less a year ago" or "It's not fair to pay 100,000 sats for a product, because some people four years ago paid 0.01 BTC for it". In both cases, it's not the merchant's fault; it's just the nature of inflation/deflation.

Merit sources are more than they were few years ago. sMerits have increased. It's natural, therefore, to reward more generously.