I think "talent development" is still valuable if you find genuinely high agency/curious/hard-working people. I bet you that senior dev, when they were less experienced, would have been a rewarding person to help develop.
I think the problem is that it's really hard to identify people worth taking a risk on developing, because during interviews everybody puts their best foot forward. Typically people use some kind of proxy for this like education or prior achievements, but those are far from perfect (and in fact, both are heavily gamed such that they are rapidly declining in value as a signal) because people will have varying levels of motivation throughout their life and in different environments, and people lie/exaggerate. You can also filter on how much they've developed themselves/been developed, eg how well they perform in a coding interview or what kind of personal projects they've done, but that's arguably just filtering on experience and also subject to gaming (people do these things just to get a high paying SWE job and that drive isn't necessarily there after they have one).
Also, you have to be willing to let people fail or struggle with tasks (you think are/that are) beyond their current skillset to let them grow. To a certain extent people can be trained to persevere through or creatively work around problems, although I do think there is a lot of variance in how well people pick that up. I've found that being too willing to help with these problems is a major reason people don't develop those skills themselves - it's just hard because they're often a source of frustration or stress for the other person, and you know you can probably solve it, and they might know you can probably solve it, so you have to be the bad guy and make them do it anyway.
I recently made the first hires at my startup and handled everything from the job description to talent sourcing to interviewing to onboarding, looking at early career people. Because the hiring market is so favorable to employers right now, I got a ton of applications and managed to hire some really great people. One thing I noticed is that the best candidates tended to be "unique" in their resumes or even their way of contacting me about the position, and they also had strong interests such that they had deliberately gone out of their way to learn new things beyond trivial stuff like "side projects" that amount to following a tutorial. Sometimes a resume might suggest that, but in an interview you could see that those interests were purely surface level; I also designed a pair-programming interview designed to put them way out of their comfort zone as a way to evaluate their perseverance and creativty. So far the agency and curiosity my hires demonstrated has extended into their jobs, and I'm really happy to be able to develop them further, because I can trust that they're going to be active participants and not just "some person who wants a job" that expects to be spoonfed.