I've been at AWS for almost 6 years now. It depends on what you mean by "internal tooling". But considering all the tooling I've used over the years at least 75% of the internal tooling that was in use when I joined is no longer in use as it has been replaced by newer, better versions of what came before.
Things definitely move at a slower pace than at new startups, but systems within AWS still change at a pretty fast pace for such a large organization. A fair number of employees don't stay past two years because of how compensation works, so they don't stay long enough to observe tooling changes, and are left with the assumption that tools are sacred. The reality is that it takes about two years between major rewritten versions of most tools. Then there is a leap forward, stasis for a while while feedback is gathered and the limits of the existing tooling are found, then in roughly two years there is another leap forward, etc. This churn requires work to keep up with, so some teams also fall behind if their product team prioritizes features over keeping up, so they may also be stuck on old versions of tooling for even longer.
So in summary I'd say yes in the short term some of the tools appear sacred. In the long term pretty much every internal tool or framework is discarded and replaced by newer versions on a fairly regular cadence.
Things definitely move at a slower pace than at new startups, but systems within AWS still change at a pretty fast pace for such a large organization. A fair number of employees don't stay past two years because of how compensation works, so they don't stay long enough to observe tooling changes, and are left with the assumption that tools are sacred. The reality is that it takes about two years between major rewritten versions of most tools. Then there is a leap forward, stasis for a while while feedback is gathered and the limits of the existing tooling are found, then in roughly two years there is another leap forward, etc. This churn requires work to keep up with, so some teams also fall behind if their product team prioritizes features over keeping up, so they may also be stuck on old versions of tooling for even longer.
So in summary I'd say yes in the short term some of the tools appear sacred. In the long term pretty much every internal tool or framework is discarded and replaced by newer versions on a fairly regular cadence.