Why do we have so many "chari's " (basically Acharyas) among Tamil Sri-Vaishnavas (Iyengars), but hardly any chari's among Smarthas (Iyers)?
Acharya means preceptor
So it is strange that it is not used too commonly as a suffix in Smartha names
Chari suffix in Iyengar names is usually an add-on to forms of Vishnu (Narayana).
Veeraraghavachari
Gopalachar
Varadachari
etc
And the form of Narayana most extolled in Tamil country is vAsudeva (KrSNa) who was a preceptor (who taught us the Gita)
Smarthas, with. a more diffuse theology, didn't pick on the "Acharya" suffix
There is a more plausible explanation -
The centrality of the Guru-shishya parampara in the Sri-Vaishnava tradition
As opposed to Smarthas where I think the guru-lineage is less central to one's identity