Since you are just using inner joins you normally simplify the query to smth like this:
SELECT ve.name AS Company
, SUM(pr.cost) AS Revenue
FROM products pr
, sold_products sp
, vendors ve
, markets ma
, sales_campaign sc
, packet_headers ph
, packet_details pd
, sales sa
Where pr.productId = sp.productId
And pr.vendorId = ve.vendorId
And ve.vendorId = ma.vendorId
And sc.marketId = ma.marketId
And sc.packetHeaderId = ph.packetHeaderId
And pd.packetHeaderId = ph.packetHeaderId)
And sa.packetDetailsId = pd.packetDetailsId
And ve.customerId = 60
GROUP BY ve.Company
ORDER BY pr.Revenue DESC;
Please try if this works and if it is faster and let me know.