Learn English – the correct usage of “those”

I've heard it said that "could care less" is meant to be ironic, but I think this is just justification for the bastardisation of an English phrase.

Here we go (from World Wide Words):

There’s a close link between the stress pattern of I could care less and the kind that appears in certain sarcastic or self-deprecatory phrases that are associated with the Yiddish heritage and (especially) New York Jewish speech. Perhaps the best known is I should be so lucky!, in which the real sense is often “I have no hope of being so lucky”, a closely similar stress pattern with the same sarcastic inversion of meaning. There’s no evidence to suggest that I could care less came directly from Yiddish, but the similarity is suggestive. There are other American expressions that have a similar sarcastic inversion of apparent sense, such as Tell me about it!, which usually means “Don’t tell me about it, because I know all about it already”. These may come from similar sources.

See scalability (Wiki)

scalability is the ability of a system, network, or process to handle a growing amount of work in a capable manner or its ability to be enlarged to accommodate that growth.

In the given cases,

tools that could help make teachers better, at scale

implies those that could measure up to the size of the task.

people who can do great things at scale.

similarly implies people who can do great things when those things manifest in a real-life (larger) systems. It is easier to demonstrate a prototype supersonic aircraft, but extremely complex to build a really usable/ commercial product of the same design concept.

We do not say on a large scale in this context, but instead we say at scale, because the magnitude could either increase or decrease from time to time. Adapting accordingly and producing comparable results in all cases is a challenge in itself. Think prosthetic & orthotic devices, for one.