I tend to agree.
The when its comes to weed surely the gangs have a well established manufacturing process, supply chain and customer base. If any gangs product/service is not up to required standards the customers will buy elsewhere. I imagine it's been like this for decades and as a result gangs provide what customers want. Customers don't seem to have any ethical type misgivings about buying from illegal sources.
Any none criminal supplier, post decriminalisation, will have a hard job undercutting the gangs who don't seem to have much in the way of typical overheads such as taxes, minimum wage, insurance, sick pay, pensions etc to cover in their costs. Plus the gangs have ways of dealing with legally compliant competitors who are perhaps not willing to resort to retaliatory violence/arson etc.
So where does that leave the customer, buy at higher costs from a regulated/taxed supplier or buy from their regular cheaper source?