If enough people in our generation take this approach, I think it will be very good for science. It is a happy medium between the old system of "everyone gets tenure eventually" and "no-job-security eternal postdoc" of the last few decades.
Science is inherently risky enough without also forcing everyone to essentially become an entrepreneur. That phenomenon is likely behind so much of the exaggerated findings that are getting published.
Most PIs I know would prefer to spend more time in their lab.
"Hire me to do the things you wish you were doing, and in the process damn yourself not to be able to do them" is a steep ask for a lot of labs, especially small ones.
So, in other words, someone perfectly suited to be a PI, a more prestigious and better-paying position with more freedom.
Our institution has one you can ask to help write/review/correct grants. They are pretty useless because they cannot possibly understand the science each individual lab is engaged in at an adequate level. Usually they just offer superficial suggestions/corrections.
Ultimately, though, I'm afraid I can't summon too much sympathy for a PI who thinks this way, because they knew exactly what they were getting into when they accepted that promotion. It is common knowledge that the tradeoff you make upon becoming PI is that you get the authority to direct the research aims while sacrificing the ability to do them yourself.
Exaggerating somewhat, a PI gets 100% of the intellectual freedom and responsibility, and has 0% of the fun. A grad student or postdoc gets 0% and 100%. I was looking for something like 50%/50%.
Right now, rather than being at 100/0, I'm actually at something like 100/50.
Hiring a staff scientist will send me towards 100/0. Which means not only do I have to think "Can I afford you?" but "Do I want to afford you?"
The amount of time you have to spend writing grants is a function of: 1) how much money you are burning, 2) how much help do you have writing, and 3) how good is your science (better science will be more successful).
No doubt I hurt on #1. But I think I help enough on #2 and #3 to compensate, and therefore I don't think my PI spends a net larger percentage of time writing with me than he would without me. Anecdotally, over my time with him, I think has been a slow decrease in the fraction of his time he spends writing.
I think there's a space where yes, your impact on #1 is probably offset by gains in #2 and #3. But there's also a space, where I'm at right now (and I suspect many new investigators are) where your impact on #1 either moves a staff scientist outside the realm of possibility, or simply dramatically increases the likelihood of stochastic funding failure unless you're literally god's gift to the research world.