Because it’s about competition. If you have a 10% market share and you use that 10% market share to expand into other markets then you’re increasing competitio

Because it’s about competition. If you have a 10% market share and you use that 10% market share to expand into other markets then you’re increasing competition. But if you have a 90% market share, then you’re not simply just expanding into other markets, you’re eliminating competition from those markets. Imaging you have a birthday cake but you said only your best friend could eat it. That would be unfair to the other guests. But if everyone turned up with their own cakes and offers up slices to other people, it then means everyone gets cake and it doesn’t matter as much who you give your cake too.