To get users to Use kra canal, it has to be deep and wide enough to Allow big supertankers and massive container vessels to pass both ways simultaneously. Maybe half a km wide.
And toll must be cheap as it saves only 3 sailing days. Unlike suez and Panama which save weeks of sailing.
Plus a massive port must be built to accommodate transhipment for container oil and other bulk commodities.
Plus tunnels to link North and south highways, railways telecom and power lines disconnected due to tunnel.
If its built, the centre of commerce and industry in Thailand will Shift south.