Not sure where in that link shows PC games sales are lower than 30% when removing Switch
In fact including Switch by the graph it is no lower than 16% for PC and depending how much of physical is PC it go higher.
But let’s pretend PC had no physical (it had like Elden ring showed) that means 84% needs to be split between PS, Switch and Xbox.
Let’s say Xbox is 10%… that left 74% to PS and Switch… around 37% each?
Now let’s remove Switch… you have 37% + 16% + 10% = 63%… 16 / 73 = 25%.
So between PS, PC and Xbox… PC has at least 25% of the sales.
Remember that not including PC physical and assuming PS had at least half of what of PS5/Switch %… if Switch is higher the PC % increases too.
So ~40% PS, ~30% PC and ~20% Xbox I showed is pretty close to what that graph shows.