Have been following US tobacco regulations professionally for about five years. US FDA appears to be regulating by inaction. For example, only two modified risk product applications have been reviewed in that time (the second, currently under review, is for Philip Morris' interesting electrically heated cigarette). The first (Swedish Match snus) was denied - years after it was submitted.
Several hundred new product applications have been submitted, but only a few have progressed to review. Most were rejected early on procedural grounds. So far, the only marketing orders granted are for Swedish Match snus products. Rejected new product applications are not made public, so it's unknown what new products were the subjects of these applications.
There's been virtually no enforcement of new tobacco regulations to date, but FDA's Center for Tobacco products is funded at hundreds of millions of dollars from tobacco manufacturers' user fees. Should FDA choose to enforce its regulations, it could have the resources to do so.
This strategy is expected to produce a chilling effect on innovation. What manufacturer can afford to develop new products for the US market when it will take years for FDA to review them and they will almost certainly be denied access in the end?
Under new anti-regulatory US administration, expect legislative efforts to modify the FSPTCA to gain ground. Know of two currently - one would modify the predicate date for substantial equivalence so that ENDS products would not have to meet the FSPTCA's high standard (appropriate for the protection of the public health) in order to remain on the market. The other would create a separate product class for ENDS.
For the moment, FDA's attention does not appear to be focused on products used primarily for cannabis, but it's suspicious that these products have been named in FDA rules and guidance. Time (probably quite a lot of it) and cannabis-specific lawsuits would tell.