Neither of those guys were making anything last year, you don't think Smith would have been giddy to go from 1 year left at $700k to a four year $20 million deal? Unlike a Jake Long these guys were at serious risk of having a bad year or getting seriously injured and ending their careers making almost nothing. Its risk vs reward, if Long has a bad year, oh well he's already filthy rich, guys like Hartline and Smith would be taking a huge risk by turning down a relatively big contract for them.
There is certainly a tipping point which is why I didn't include guys like Fasano or Starks as I doubt they play ball but I would bet a big chunk of change that Hartline and Smith would have happily signed an extension.
The same rule applies to the other young guys that look like keepers, extend them as early as possible. For example Ireland should be talking to Reshad Jones' agent NOW.