SMIC is running into real problems without EUV. Just because they are able to produce something at 6/7nm, it doesn't mean that it is efficient or competitive. Right now, they do it because of strategic considerations.
Why is ASML's market cap so high? Only ASML has commercialized EUV at scale. In order to generate enough EUV consistently for use in lithography, the equipment fires lasers thousands of times a second on a drop of tin. It's really hard, but you can replicate this or develop another method given enough time and money.