That link doesn't say anything about the inevitable updates for Windows 10 being free.
In some ways, I wish Microsoft would charge for ongoing security and compatibility updates after a reasonable period, but in a transparent way.
Useful lifetimes for PCs are increasing (forced obsolescence aside) and it's not a viable business model to expect MS to sell a copy of an OS one day and then support the same OS indefinitely with no extra revenues. However, clearly a lot of people are happy with what they've got and don't feel the newer versions of the OS getting pumped out to try to increase those revenues are actually an improvement, so that model is unsatisfying for all concerned.
In contrast, charging a modest and honestly advertised fee for long term support after a reasonable initial period of free updates included in the original purchase seems like an everybody-wins proposition. Customers who want to stick with, say, Windows 7 for as long as their home computer works/it's their corporate standard/someone in IT likes it have the option to do so, without giving up on useful updates for things like security or compatibility with new hardware or networking standards. Customers who are interested in more radical change can buy newer software instead. Microsoft gets enough money to run a viable business model either way. As long as everyone knows what the deal is up-front and the update/fees are optional (so if you don't pay then you don't get the updates but you also don't get your existing software artificially nerfed) I don't see any huge downside here.