One reason could be a lack of incentives. For example, the Science based target initiative (SBTi) does require permanent carbon removal to fulfil Net Zero targets but does not incentivise deployment of removals before target dates (2030 and beyond). We hope that  the SBTi Net Zero standard will include guidance on carbon removal in the future. 

Relevant changes could enhance the credibility of the SBTi standard by clarifying how Net Zero-aligned companies should approach near-term purchases of permanent carbon removal. SBTi has promised additional engagement on this in 2023. See CarbonPlan for more information – https://carbonplan.org/research/sbti-carbon-removal