SREs get treated like a cost center and no career progression. The majority by volume of sysadmins were automated out by the wave of cloud vendors, leaving over a decade now of undertraining. Those who are left are mostly mission critical unfireable greybeards.

SWE get to work on new products and get career growth towards bigger and more interesting projects as reward for delivery

Of course people focus on where the opportunities are. It's not the fault of an individual company but an overall industry mindset. "Reward it or lose it" should be a mantra of availability in technical industry expertise.

It's really unfortunate. Cloud allows rapid iteration, but doing a bit of self-hosting/colocation is such an insane cost savings that I think a lot of folks are really missing out on. I know at least 1 startup I worked at that would've had a more comfortable runway had they not went wholesale into AWS instead of playing it smart with hybrid. Paying a small team of folks even an astronomical salary to keep a small number of servers up 24/7 and use cloud where it makes sense (S3, elastic CI/CD with EC2) should still be saving some companies 6+ figures a month.

You train them, remember that? :D

This is legitimately what we're doing. We're bringing in really junior folks and spending years training/improving them. Unfortunately that doesn't help now. I thought it would be easier this year to hire due to COVID and layoffs, but it just hasn't been.

Did you post in Who’s Hiring? :)

The company I work for did. I asked to edit the post to add my specific posting and they said it couldn't be done. It'll be there next month though!

It helps now if you started a year or two ago. ((sad trombone))