Modern turbines are very, very optimized, because they are used in systems like power plants. Here, every fraction of a percent of efficiency is massive. Hence, modern turbines are optimized as much as many, many smart people can do. This in turn means, even if Tesla just designed something pretty efficient many years back (which would be really impressive), it just loses in modern, industrial applications.

Like, people have been looking at better ways to generate electricity from nuclear or fusion reactors. But current steam and steam turbine systems have been optimized so hard and far, it's extremely challenging to find anything better than just heating water and jamming it through a turbine. Because current steam turbine systems are just that good.

It reminds me of the recent thread about hypothetical usages of the recently discovered and not yet confirmed room temperature super conductor. So many people are just arguing that a potential material that was discovered 2 or 3 months ago would be worse than silicon based electronics we've been optimizing for 40 - 50 years, or steel-based long range transfer we've been optimizing for longer.

As for current turbines, I remember they are grown from a single crystal, as any kind of joint would be a breaking point in the material. They also have to abide by very strict size restrictions, at that RPM a single millimeter wobble can have catastrophic damage.