Many reasons.

Summer: people travel and do family things.

Economy: people have more money to expand hobbies and interests.

Fatigue: people are just tired of the gun issues and need a break from it

Urgency: no proposals that would cause a panic buy are on the horizon leading to renewed interest.

Threats: based on the hatred and lack of respect from the gun lobby against a myriad of companies targeting gun owners, many are keeping a lower profile until we see some changes. This is from social media to banking to general tracking of innocent people.

We can go on and on. Welcome to the summer of 2018.