The real question is “why is it not possible?”

The answer is NOT “because it’s hard coded every 210,000 blocks.”

No. Not even close. The real answer is “Because I say so…and I can say so because I run my own node…and my wallet connects to my node and I will not accept payment that doesn’t follow all the rules.”

Back then, neither miners nor businesses thought users had any role. Devs knew better. Most devs at least.