Amusingly enough, the tugs not uncommonly have more thrust.
Large ships are _heavily_ optimized for the common case, which is sailing at about 13.5 knots. They take a very long time to get up to speed because their propulsion is sized to be just enough to overcome resistance at their typical cruising speed.
Consequently, it would be difficult to get another ship up to any sort of speed in a short enough distance. Even if you could, the the momentum is absurdly high so it's much more likely that any sort of chain would snap, or the attachment point would break than that the aground ship would actually move.
(The aground ship has a deadweight of approx 200,000 tonnes)
Expanding on your comment, it's analogous to torque vs speed in cars. You wouldn't use a Ferrari to tow just because it has a high top speed and lots of top-end power. You'd use something with high torque down low and good gearing.
Similarly, tugs use different propeller setups (e.g. ducted props for extra power, or vectored systems such as azimuth thrusters or cyclorotors for extra manuverability), which just cause extra drag if all you're doing is cruising at a fixed speed throughout oceans.
A big container ship trying to tow something is not unlike having a high-speed racecar spin its wheels. It's not designed to put that torque down at low speed and lift a big trailing mass.
Large ships are _heavily_ optimized for the common case, which is sailing at about 13.5 knots. They take a very long time to get up to speed because their propulsion is sized to be just enough to overcome resistance at their typical cruising speed.
Consequently, it would be difficult to get another ship up to any sort of speed in a short enough distance. Even if you could, the the momentum is absurdly high so it's much more likely that any sort of chain would snap, or the attachment point would break than that the aground ship would actually move.
(The aground ship has a deadweight of approx 200,000 tonnes)