I've known dozens of people in pretrial for a decade or more, it's not uncommon. Some are acquitted, most plead out or are found guilty of something at trial.

Under US law, pretrial detention is not prison. You are technically not being "punished" even though generally the conditions in pretrial are vastly worse than in prisons. (I did a deposition with a jail warden once and asked him why this was: "Because these facilities are designed for the average stay, which is 30 days if you run the numbers. Sure there are people here for a decade, but most people pay their bail within 24 hours.")

Technically most states have pretty short Speedy Trial statutes which require the gov to try you within several months of arrest. This almost universally doesn't happen because the defendants don't have all the information necessary for their defense, and because they want to run motions to try and quash any existing evidence.