As Ken so astutely pointed out, normally Dawson would have been given more time to produce (certainly beyond his rookie year when he was mostly injured) but it wasn't feasible because the Patriots hit on
three UDFAs that developed into quality players, Jackson, J. Jones and Crossen, and when combined with the other strong CB vets it simply wasn't possible to give Dawson a more reasonable time to develop.
IMHO Cyrus Jones was a somewhat similar story. The first year he was thrown to the wolves as a returner and surprisingly (given his return ability in college) seemed to develop the yips and had a lousy year as a returner. The next year (2017) he was injured all year and at the beginning of 2018, coming off of injury, he simply couldn't beat out a group of CBs that included Gilmore, Jason McCourty, J.C. Jackson, J. Jones and Crossen. That is a similar story to Dawson except Dawson had 2nd round pick Williams to compete with also.
However, it isn't like Cyrus Jones is now working at the neighborhood Walmart, he has landed on the Ravens and is expected to be their starting nickel CB,
"even though the Ravens' depth chart at cornerback might be one of the deepest position groups on an NFL team."
https://www.al.com/sports/2019/08/cyrus-jones-feeling-really-really-good-with-ravens.html
So: Cyrus Jones appears to be doing fine with the Ravens, he simply got beat out by a bunch of great UDFA CB prospects on the Pats. We will have to see if something similar happens to Dawson on the Broncos.