There are two ways for them to block the VPNs:
- blocking those IP addresses
- detect and block the VPN service stream
If they are blocking the IP addresses, then the VPN provider need change the VPN servers IP address as always (but many VPN providers are already doing that).
They can detect easy the classic PPTP and L2TP, but many new Point2Point encrypted stream technologies are already available, and many business companies (example banks, etc...) are already using, so that is not a "solution" for blocking every encrypted data streams.
There are already minimum 4-5 different VPN encrypting ways, what already available and on use.
But i think, they just want to ask money from VPN companies.  It's logical. 
And the "main" reason is secondary : Many people are using arguing from the leader party online with VPN, and they really not like those things. 
(Example one high rich chinese guy is making protest videos and he put to youtube where he is talking very rude from the chinese leaders, etc...)
But if they will really do it the all VPN banning, then need renting an outside remote desktop connection in other country, and problem solved.  But yes... then Google Play will be really banned then and you must go example to HK for update it.  | |
It's logical. 
But yes... then Google Play will be really banned then and you must go example to HK for update it. 