Many of the top FA RP'ers signed recently were disasters due to injury, too. It's part of the risk, but also part of the "miss factor."
I get that the contract makes their misses more acceptable, but it doesn't change the idea that they miss more often.
Afterall, most are RP'ers because they weren't good enough to be starters, although that notion is changing, and we're only talking about the top FA pitchers signed, recently.
I know a lot of starters have "missed," many due to injuries, and I have said I'd rather we trade for a good to great SP'er than sign one, but I still think they miss less often than the best RP'er signings each year.
The list I provided has a whole lot of complete failures and many nearly complete failures.
Some, like Chapman and Jensen, from like 5 years ago did well, but the vast majority failed.