I think he considered heroing to be a temporary phase in his life then.
I don't think Jason coming back in any way contributed the end of the idea of a Forever Robin. I think that idea died with Nightwing. If you read 1970s comics with Dick in college, it was definitely a thing in the letters pages - should he stay Robin or take a new identity (costumes also discussed). I would say that, via the New Teen Titans, in the early 1980s the decision had been made that Robin was a role that grew with Dick. He was regarded well as a hero and as an adult by numerous other heroes in that era. But then they wanted a Robin with Batman again, and so Dick transitioned to Nightwing. It was very couched in the language of outgrowing the role. I think that once that had happened, Robin could never be a "forever" role again. So the decision was made before Tim ever existed.
Like I said, don't think forever Robin was ever in the cards - that ship sailed with Nightwing's creation to me. Certainly Damian did edge Tim out in the narrative (Dick took it away - a post-COIE Bruce-like action I hated and found repetitive). In a meta sense, it was absolutely taken away so that Damian could have the role. But the same is true of Robin being taken away from Dick - it was a shift that only happened because they wanted to bring in Jason as Robin. It was just a much more satisfying story (to me), because in-universe it was a progression instead of a loss. Then the post-COIE version made it a loss. Added angst and drama, but was the start of a dysfunctional Batfamily dynamic that I have grown to dislike more and more. But sells well, so DC doesn't care what I think.I don't see how Jason takes anything away from Tim. Jason could be Red Hood doing his own thing and Tim could've still been a forever Robin because he wanted to, he chose it. It's completely Damian who edged him out.
Another thing about early Tim is that, in addition to not planning to make a lifetime work of Robin, he had a very unhealthy view of Batman and Robin. Firstly, with how he wanted Dick to give up his life and be Robin again But secondly, with Batman in general: he was the perfect, always-right, and if you were with him and did what he said, then you'd be fine ideal (once he had a Robin and got over the violence). Thing is, the second aspect of that was not treated as unhealthy at that time. Tim's entrance was a whole lot of dumping on Jason and victim-blaming of him. Later he knew Batman better and knew his flaws more clearly (though DC still loved their victim-blaming). His idea of Robin was tied up in that thought process - Robin was an extension of Batman. That's an attitude that could never work for a forever-role. Though, that's also one he grew out of fairly early - if nothing else, him having a solo series meant he had to.
But I think if Dick Grayson, the Robin, did not stay Robin forever because it was something he outgrew, then that in and of itself redefined the role as transitional. And it wasn't even a totally new idea then, as I've referenced old letters from the 1970s. And, of course, there were the even older imaginary stories where Bruce actually retired ( ::gasp:: ), and Dick became Batman and Bruce's son was Robin. So the idea of Robin remaining a "kid role" has definitely existed for a while.