I’m certainly overlooking something but the risk seems small since it uses an open standard. You should be able to fallback to another acme provider right?
The traditional way a big tech company becomes the dominant provider is to embrace an open interoperable protocol to minimize the friction of switching from another provider. Later, when they have captured enough of the market, they extend the protocol to gradually reduce the de facto interoperability with other providers to increase the friction of switching to any other provider.
https://en.wikipedia.org/wiki/Embrace%2C_extend%2C_and_extin...
LE is great, but their SLO is significantly below our customers’ expectations. For us, Google wouldn’t replace LE, it would supplement LE for higher reliability.
Seeing more providers conforming to ACME at a price point of “free” is great for the ecosystem.
The recommended renewal cycle gives you a 30 day lead on failure becoming a problem, plenty of time for multiple retries or recovery processes to use an alternate.
The only issues I've ran into, have stemmed from DNS for wildcard certs, where a client's DNS provider is... pretty crap about updating records despite low ttls being set.
On AWS, the equivalent is "We no longer recommend this, and it's not visible in the AWS console unless you are already using it or have asked support to enable it, but it will keep working indefinitely".