4 time 500 winners command respect. AJ commented on the possibility. It certainly was being considered. The engines could have been made available with Chevy and Honda combined. Most probably not every completed engine in those two is on a car right now. Yet they decided not to do so.
Why? We probably will never know the real story but, it may be...
A) Economics, they didn't want to lose money per engine. Or lease an other at any negotiable price.
B) Their sense of gentlemanly sportsmanship.
C) Indy car quietly persuaded them not to as it would be "bad for the sport" to shut out the Lotus Teams.
I suspect answer C had is the "best possible answer" to this multiple guess quiz. But we will never know.