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.