I believe Ajax did just that. Only allowed a single sack for the season. Personally, thinking a rookie LT will come in and be better then an ascending LT doesn't make sense to me. I do not think the improvement we might get from a rookie LT will be more effective then adding a disruptor on defense. Or even a WR, which I'm not totally a fan of, but I think moves the needle more then a rookie LT.
We reached two Super Bowls with Whit locking down the blindside. I think it is unlikely we will reach Super Bowls with Jackson at LT. When we get deep into the playoffs we're going to see DLs and DCs that can isolate weaknesses up front and this year the weak link is going to be LT. At some point in that potential four consecutive games vs the best teams, which leads to hoisting that Lombardi, you are going to be affected schematically by Jackson at LT. And in that min/max environment that type of thing can and will send you home.
And beyond that Jackson is going to want to get paid. In his mind he's a LT now. Rams are probably not going to pay him, based on the fact they now have two OGs in well paid status and the RT also being paid even if it's a median contract. Avila and a young LT will be required to be part of that group I think, otherwise they are tying up too much cap value in one position group.
So if the Rams go get a LT the payoff is the long term fix at the most important spot for a QB's mental well being. They avoid putting too much cap value into one position. And they avoid overpaying a player who is probably a LG or RT. I think the failure with Boom was a wake up call for them. I think it was part of that OL awakening that McVay has had overall, where he seems to be valuing the big boys up front a bit more than he used to.
Fans will whine and complain because that's what we do. But also because OL are not sexy like players who score TDs and do silly dances. However what OL will give you is more players doing silly TD dances, so it balances out. Imagine if they hit on LT. If they do that I guarantee any complaints you may have will dry up down the road and you'll be thankful they went and got that LT when they did.