I'm no expert, but I did a bit of digging.
It would appear that one reason for the disappearance of the sword-and-buckler armed men was that as time went on, and with the increasing effectiveness of shot, the pike became less of an offensive weapon, and more of a defensive one against cavalry.
In which case, the need/ opportunity for soldiers to run out and slice up enemy pikemen in a pike-on-pike melee was no longer a common enough, or decisive enough, occurrence to justify equipping men specifically for that kind of fighting, especially by the time of the TYW/ ECW (that great scene from Alatriste notwithstanding).
Issuing them muskets instead of swords and bucklers would have been better bang for the Imperial buck- no pun intended.
Maurice of Nassau at the beginning of the 17th century tried to reintroduce these "targeteers", but the concept clearly looked better on paper than it was received in reality, and it's doubtful that many- if indeed, any- actually made an appearance outside of theoretical treatises of the time (which was probably how men armed with sword-and-bucklers found their way into a lot of the later artwork).
It is possible that some officers may have affected rodeleros equipment as a sign of rank and status, especially with such a fundamentally conservative army as was the Spanish. But this would be an individual choice, and is a far cry from representing a distinctive troop type.
Although it would be fun having an occasional and purely decorative- if anachronistically equipped- figure armed rodeleros style on a command stand, in keeping with the artistic conventions of the time.