How does the letter by john porys indicate the importance of tobacco in Virginia?

Quoted from the letter,"All out riches for the present do consist of tabacco, wherein one man by his own labor has in one year,raised to himself to the value of 200 pounds sterling"

So, tabacco, as you can see, seems to be involved in all riches and goods, traded and used. Tabacco also seems to have a high price, so if someone gets their hands on tabacco, they are considered "rich"

I cannot say this information is accurate, just how I believed the letter indicated.