Noteboom will pocket $7M for this season (in some combination of signing bonus and salary).
Some starters and some backups are on rookie deals while others are on open market contracts. For the guys on deals after their rookie contract expires the market sets their price.
So yeah, Noteboom is going to make $7M this year while Avila makes $1.17M. I doubt the Rams could have paid Boom less. Certainly not much less. And they can give Avila another $6M if they wanted to, but that doesn't make any sense. And so we will have a backup OL making more than a starter.
I think the Rams see Boom as a very valuable 6th man (and I bet we hear coaches say the Rams really have 6 starters at some point). He knows the system, is probably a leader in the OL room, can play every position on the OL except C and in all likelihood will be called on to spot start several times this year (assuming he doesn't beat out Jackson and start at LT).
AlbaNY_Ram