Considering Microsoft released the first version of Windows 7 in October, 2009 and its first and last Service Pack (#1) the following March, this OS can be considered, shall we say, mature. But the old boy still has plenty of kick left and Microsoft will not abandoned its support for it until January 14, 2020.
While Windows 10 is generally considered more secure due to its better architecture and continuous updates, the reason many people stay on 7 is its less cluttered and frankly easier to use Desktop, well-supported hardware drivers, and lower memory and power requirements. And, hey, with properly maintained security software, 7 is still safe without the Microsoft-imposed, mandatory updates in Windows 10.
With all the hype and push to Windows 10, you might think that you can’t still purchase a Windows 7 laptop or desktop. If you try at a brick and mortar retailer this is true. But online there are actually multiple choices. Both HP [site] and Dell [site] continue to do a brisk sales with Windows 7 Professional systems. The trick to finding them is to search their sites for business products. Many companies, quite happy with their existing Windows 7 PCs are still buying them. The main reason they do not invest in Windows 10 is the cost of training all the employees and maintaining a budget-busting, company-wide logistical upgrade (aka IT nightmare).
So corporations avoiding the IT nightmare is the consumer’s gain, at least for consumers who want to stay with Windows 7. Because the PCs for sale are geared to business the units for sale are solely Win 7 Professional OS. Actually, Win 7 Pro is the best version of the OS anyway.
The Care and Feeding of Your Windows 7 Investment