The actual yard stick is only EBITDA through this year, and EBIT thereafter, and moreover, it's the tax versions of EBITDA and EBIT, not the accounting versions. For starters, the tax versions use taxable income as the base, not book income, and don't add back in most non-cash items, so the threshold is much lower.

Many businesses were hit by this interest limitation in 2018 and 2019. There are dozens of articles from major tax firms about it. Yes, a business can carryforward their unused interest to a future year in which they have spare income to apply it. But that means they have to have sufficient profits and reduced loans in order to take advantage of their interest expenses. If a business is unprofitable, churn loans, or increases its debt load, the business effectively loses out on a lot of the benefit of most of its interest expense.