A lot of us would but if coaching tightening up, they can build what they have up.
Ummm until the Vikings win a SB please don't use them as a example. New England does not go and spend heavily on the offensive line and yet they are winning SB's or coming extremely close. So you don't have to spend money like that. You have to be able to coach players up.
They just spent a 1st rd pick on a LT who got hurt. (Wynn) and traded for Trent Brown 3rd rd. So I would say they invest in the OL. Solder and the dude from UH were 1st/2nd rd picks.
So yes, they invest in their OL in addition to coaching them up. Look at what rds the Saints OL was drafted in. Steelers etc....