wordpress plugin as well as mobile app stores are reminiscent of the ugly pc shareware and freewares of past 30 decades.
1. Companies
2. Private individuals who are happy to pay for software
3. Private individuals who aren't going to pay for software
The discreet notification is enough to get 1+2 to pay. Group 3 isn't going to pay anyways, and making the notification more annoying will just make it more likely that they crack it and never see it again. Most importantly, when people from group 3 start working at a company, they may get the company to buy a license (which is now a subscription, i.e. makes them a lot more money than a personal license).
A more annoying notification would likely win them very little, and lose them a lot (from people who use a different editor instead).