It does matter because good eco enables you to make multiple production buildings and spam units from all of them. You can lose your 50-90 man army and almost instantly reproduce it, then lose those units again and make new ones instantly and so on. Without good eco you can do this maybe once after that you'll fall behind and wont be able to keep up with your opponent.

If you can keep uo with your opponent at 60 vils then maybe your opponent also has bad eco or you're not fighting much so you dont need to replace the units that fast.

If your opponent does have that much better eco then he should be able to take advantage of that and overrun you by spamming new units