Tbh it's less about having to maintain it forever and more about not wanting to deal with maintaining a C++ library codebase that would widen the potential attack surface of the browser (due to memory bugs, etc). They are fine adopting it as long as it's in rust (which is being worked on, see sibling comments)

Considering firefox is a small fraction of safari's size I don't think it would fragment the web that much.

The Mozilla "organizations" are a two-headed grift piggy-backed on a non-profit shell so the IRS keeps smiling.

Firefox hasn't made a technical decision without first forwarding the minutes to Mountain View and Redmond since roughly 2017.

Every nine-figure Google wire lands promptly converts into $450 k-per-head salary vapor and off-site "all-hands," while the same week another 250 actual engineers get an email that begins: "You're talented and valued BUT-."

Servo? Jettisoned.

MDN? Gutted.

Security teams? Re-org'd into a Slack channel no one reads.

And the Foundation helpfully reminds donors:

"Your gifts don't pay for Firefox engineering."

No kidding. They pay for glossy pamphlets proclaiming the open-web gospel, first-class flights to "advocacy summits," and Mitchell Baker's $2.5 million thank-you note. Firefox isn't a browser; it's a loss-leader Google keeps in the closet for the next antitrust subpoena.