I didn't say there was a long list of better players at the same position. There might be, but that's not what I said.
I said that there were better options for the Cowboys.
When you pay money to a free agent like Hatcher, you're not just considering his exact position, but how it affects the entire roster.
The Cowboys are likely to need another year to patch all of the issues that they had this past season. By the following season they could have built a really good defense, but by then Hatcher will be 33/34; whereas, a free agent like Linval Joseph is currently only 25.
Hatcher is going to want a multi-year contract. He's already said "I don't wanna hear no talk about age, I deserve a big contract". It would be stupid to give a 4 year contract to a 32 year old DLineman that already has injury concerns.