I think it's incorrect to state that Rust 'forgot about Ada'. Rust was designed to approach safety in a very different way. Ada's take on safety has an emphasis on strong semantic typing and run-time correctness. Rust's take on safety emphasises compile-time correctness. Very different. I would argue that compile time safety is a better way to go but everything has trade-offs to consider.

Rust's borrow checker gets bad press because it forces programmers to confront their unsafe programming methodology and fix it. I think it's beautiful and ends up teaching you more rather than cultivating a culture of 'let me do what it takes to shut the compiler up so I can ship the product'. I find it very disingenuous to write the language off because it strives to be militant about safety.

Oh and Ada's compiler is super testy too! It just doesn't get the same bad press simply because far too few people use Ada compared to Rust.

I personally think that the reason people fundamentally add a moniker like 'Duncan MacLeod' to Rust is simply because Rust has gotten far too many things right and that irks dyed in the wool folks. Especially given that the choice of programming language is often enough a more emotive issue than a technical one. Having been one such person myself, I see a lot of folks spout FUD as a default position when confronted with evidence of the good design choices Rust has made. This is true.

Now that does not mean that Rust is perfect - not at all. However, it's safety features, in the face of high performance - are very compelling. Once folks draw a box around the emotive aspects and start doing objective analyses, Rust does make one pause and ponder. That's the reason why there is evidently a growing sub-culture of Rust enthusiasts even within large traditionalist companies like Google, Microsoft, Intel and Arm, to name a few.

Back to the point (!) Ada simply became too niche despite aiming to be general purpose by design. Today the open source Ada community is small compared to the Rust community and I think that is a huge problem for the perpetuation of the language, irrespective of the subset of high profile folks who've switched to it from C.

A large and vibrant community is the reason why Rust's future holds more promise. The language evolves by open source consensus-by-merit (on Github!) and that's a very strong proposition for it's future. Balancing nimble-ness and backwards compatibility has worked well thanks to the editions feature (something that C++ has now borrowed from Rust).

I'd love to see Ada succeed but at present I personally think Rust stands a better chance. Time will tell.