You might be absolutely right that gelatin is "cheaper" than cement, but because prices don't incorporate externalities (carbon included) we can't use them for comparisons of this type.
But that's what you get when your entire economy is based off of endless growth and profited market relations. I'm not an advocate of central planning for replacing markets, but definitely an advocate for production being about meeting needs instead of generating surplus value for private owners.
I agree with you about biological health being an environmental concern, by the way. But I'm willing to bet you and me might see things a bit differently from the regular crowd here. When most people think of the environment, they think of oceans, trees, rivers, air, etc.
Namely you need to look at the total cost of manufacture, especially with respect to the environment and/or CO₂ impacts.
This process, excluding inputs, has a lower CO₂ impact than traditional concrete. It also, currently at least, produces a less useful concrete, as it isn't as strong.
The question is what is the net environmental and CO₂ impact when you also include the inputs.
One area where this new process has a positive impact: * No need for virgin river sand, although it is unclear if desert sand could be used. At least this would be a good way to "recycle" concrete, which is notoriously hard to re-use.
One area where it has a negative impact: * This concrete is no longer vegan friendly. Although to be fair, many plantation woods are not strictly vegan either, since may plantations directly lead to a lowering of biodiversity and/or loss of animal habitat. Sand mining is also typically not "victimless". * Requires a more diverse input/supply chain. Although the article doesn't really go into the impacts of this, so it's hard to estimate how bad this is. For example, do we need a kg of gelatine per kg of concrete, or per tonne of concrete?
This is why, desire being in a desert, Dubai imports its sand! (https://www.bbc.com/worklife/article/20160502-even-desert-ci...)
There are farmers experimenting with “vegan vegetables”: vegetables grown without manure, but plant-based fertilizer only. E.g. https://www.partyfortheanimals.com/inspiring-pig-farmer-beco...
However "Vegan" things is definitely a tricky subject… for example cars often have leather seats and/or steering wheels. And it can be quite hard to get a "decent trim" car, and _not_ get leather. Tesla do offer "non-animal-leather" seats, but not all manufacturers have such an option.