Will housing inventory levels improve next year?

So -- after seeing a 20% decline in inventory levels between April 2017 and April 2018 -- are we likely to see inventory levels start increasing again in 2019? Again, I don't think so, and here's why....
To reverse this trends of declining inventory we would need one or more of the following to happen in our local market....
- A decline in buyer interest / activity -- which only seems to be happening (slightly) because of lower inventory levels.
- A decrease in the rate of people moving to this area. Seems unlikely -- we're one of the fastest growing areas in Virginia.
- An increase in the rate of people moving out of this area. Seems unlikely -- it's pretty nice here, unemployment is low, quality of life is high, etc.
- More new homes being built. This is not currently happening at a very rapid pace in and around Harrisonburg.
- Sellers selling who don't have to buy. This could be older homeowners who are moving into a retirement community, or people selling to then build themselves a home on their own land, etc.
Again -- none of the changes above seem likely to happen at a scale that would allow inventory levels to see much, if any, of an increase next year. As such, I am expecting we'll see relatively similar inventory levels next Spring and Summer.