Xi has been purging Jiang's people/influence on the Central Government for the last few years to strengthen his ruling. Originally he was going to leave Ma alone as he has proven himself to be useful.
But 2 things happened- 1. people start to idolize Ma the businessman over the party's absolute rule. 2. Perhaps as a result Ma is embolden to speak out against Xi's government directions.
So now Ma has to go. Ma knew this and that's why he resigned from Alibaba's Chairman position, but it was too late. Ant Financial, with its main backers from Jiang's gang, was put to a standstill. This is only the first step. Expect the party to eventually to take over the Alibaba group (国进民退). No private civilian will be allowed to gain this much power again.
https://time.com/5926062/jack-ma/
“There is no so-called [Ma] era,” read a recent headline in the CCP mouthpiece People’s Daily, “but only an era that has [Ma] in it.”
Anyway, to quote House of Cards-
“Such a waste of time. He chose money over power, in this town, a mistake nearly everyone makes. Money is the McMansion in Sarasota that starts falling apart after ten years. Power — is the old stone building that stands for centuries. I cannot respect someone who doesn’t see the difference.” - Frank Underwood