Since 1990, the world has changed so much we cannot just take the 1+inflation factor, slap it on the 90s price and call this the supposed price of today.
Marketing has changed, mass production has changed, shipping has changed, sales platforms has changed... Those sectors heavily impact the prices and all of these were made a lot more efficient during the last 30 years.
The 225$-140$=85$ difference is more likely due to the gain of efficiency than to Nike wanting to be kind with its customers and not adjusting to price to inflation factor. I'm even sure that you took the profit on one pair in 1990 < its inflated value in 2020, so Nike is winning on both sides.
at the end of the day, it’s all about the money and they know that regardless of what they set the price at, product will still get sold and profit will be made