What is the aim of Paralles?

I am using version 10 of Parallels. I installed Sierra and the space key started not to function. I searched for the problem and it turns out to be a known issue. The resolution by Paralles is: http://kb.parallels.com/en/123842 It means that you have to pay about 50 euros and upgrade to a newer version. A further seaerch provides a simple solution: http://kb.parallels.com.metacomment.io/en/123842 What is the aim of Paralles? Besides this, a window appears asking if I want to upgrade to a newer version once in a while. In that window there is an option where you can select "do not show this window again". Selecting the option that does not help. Parallels will show the same upgrade window again and agin. What is the aim of Parallels? Maximize profits and exploit customers?

 

"Maximize profits and exploit customers". This is the reason I stopped upgrading after PD10. I'm running OSX Yosemite PD10 + Win10 and no issues. I may upgrade to El Capitan to see if everything still works but I'm not paying $50 every year for upgrades. Not to mention the restrictions Parallels has introduced starting w/ PD11 like Memory size in VMs.