Zero to one is considered “R&D” and that’s what this entire thing is about.
Is there a good chance of recategorization pushing a very marginal business off the cliff? Sure--that Twitter thread, where there are enough details to read in, has a lot of examples of marginal businesses having trouble (mostly because of not being able to plan in the change, which really sucks). But you don't have that on day zero, and going in with the aim to be that very marginal business is probably not the best of ideas. It's not a day-zero problem, and I am struggling to see where a small business with a business plan that was previously worth executing on is now not worth it because of this change.
To slightly simplify: it forces startups to pay taxes on profits that only exist on paper, with cash that is now much more scarce
For a clearer picture on this it’s helpful to include the actual tax amount. With a corporate rate of 21%, the tax would be about $12K.
Now that’s not zero, but it better shows the actual cost born in year one under this plan.
The later years are important as well. As profits continue to flow in, the rest of the cost can be deducted from it. So it doesn’t disappear.
Though you do lose a bit from the nature of present nominal being inherently worth more than future nominal amount. With todays higher rates, that’s an even larger factor.
Affected small businesses suddenly need to increase revenue or cut costs by 20% just to keep their business solvent. Most small businesses do not have the structural elasticity or capital reserves to absorb that, nor do many business plans. In the very long term it notionally all evens out but most small businesses don't survive that long and these large new costs of doing business will reduce the survival rate even further.