I do agree. The decision not to sign Armstead, whether because Watson waited to long or not, was a mistake that has led us to where we are now. They had to get a LT in that draft and Penning was seen to be the best one available where they picked. And he may have been, but that doesn't mean he was ready to start. They should have taken another player, moved back, or just have not made the deal with Philly include getting two first that year. But taking Penning at that spot meant that they were essentially forced to rush him to start because they had no other LT option. That contributed to him never developing to the point he needs to be. He was always likely going to take a year or two to develop.
Then they had to take Fuaga. Luckily Fuaga looks to be the real deal and was solid value where they picked him. But, if they had signed Armstead back then, the entire OL would look so much better and you could have Armstead at LT and Fuaga at RT until he moves to LT when Armstead retires. And maybe we would not have taken Penning and instead used that pick on a young DL, WR, TE, or Guard. Lots of possibilities for how it would have gone, but yes, not resigning Armstead was the beginning of the downfall of our OL. And yes, we are really lucky that Cleveland guaranteed him all that money because we would be worse off now having made the Watson trade.