For about a 7 year stretch that wasn’t true. High round picks became dead weight on bad teams due to cap ramifications (their contracts were front loaded with massive signing bonuses and relatively low salaries).
Today a #1 draft pick has significant more value than it did three years ago because the cost is so much lower.
If you sign one as a free agent, he’s going to cost you every last penny he’s worth to that point and he’ll only be with you for as long as you are willng to pay top dollar.
Well, sure, but that’s not really relevant, because that’s all understood and a given and a high pick rookie isn’t going to be substantially cheaper. Until the most recent draft a #1 overall pick was going to cost you substantially more than even a massive FA pay day.
As an example, Matt Ryan was the #3 overall player taken in the 2008 draft.
Contract? 6 yr/66M/35M guaranteed.
Big Ben signed a contract extension a couple months before Ryan was drafted. It was the biggest contract in Steelers history.
Contract? 8yr/108M/36M guaranteed
That’s how fucked the system was.
Note that the per-year is sort of irrelevant, it’s the ‘guaranteed’ money that matters, and those guys were getting effectively the same guaranteed amount.
Successful teams sign FAs during their prime years, typically their first big contract after their rookie contracts expire, and avoid overpaying for past production.
The one exception to all this is the RB position, where drafting someone always makes more sense. I can think of only a very few starting star RBs that were allowed to walk and then went on to have monster success elsewhere. RBs fall apart quickly and they’re fungible, so overpaying for one (even if it’s a contract extension) is almost always a bad idea. You can go from setting records to washed out in 2 years as an RB.