I play a lot on boards with mixed scenary to putting everything out of LOS is ussualy not an option.
I'm fortunate to have 3 LGS that are about the same 20-30 minutes away.
2 of them have quite a few tables and a good amount of scenery.
However the one I tend to go to these days has only 2 tables and most of my friends.
I'm generally painting there so it isn't that much of a hardship.
The 40k themed table has a good amount of terrain, the other table is themed for AOS and the amount of terrain is perfect for AOS.
However it really suck when we try to play a game of 40k on the AOS table.
Several of the players tend to bring their box of terrain from home in the chance that we will have to play on the AOS table.
This might be a solution you could employ if you are finding the terrain is a little thin in your area.
And the cost isn't that prohibitive, let me explain.
If the table you are playing on at your club or LGS is modeled after the typical Adeptacon table setup, it will be a 6x4 table with about 6 pieces of terrain on it.
That is 1 piece of terrain for every 2x2 section of the board.
If you and your opponent each bring 1 piece of terrain, you will now have 8 pieces of terrain on the table.
Then if you shorten the board to 4x4, you will have 2 pieces of terrain for every 2x2 section of the board.
You just doubled the density of terrain by grabbing 1 thing out of your closet, and asking your opponent to do the same.
If you and your opponents agree to build and paint 1 piece of terrain each year, then in 2 years you'll have built the board back up to 6x4 with 2 pieces of terrain in each 2x2.
If you do that by yourself and have nothing in your closet that could pass for terrain, then it will take you 6 years to flesh out that table.
But I think everyone can find, build or acquire at least 1 thing that could pass for table clutter in a year, and they likely have 1 or more things already.
Depending upon how close the bond is with the club and the LGS you might be able to organize a terrain refresh event.
This consists of gathering small donations to pool together for the purchase of club terrain.
This works if you are playing at a LGS or Club instead of at someone's home.
The other part of the event is you get the players in the club to help paint the new terrain.
This has a 2 fold effect, terrain that people helped pay for, or build or paint they tend to take better care of.
The store in my home state before I moved had a bad problem of players trashing the store terrain.
So the store owner and a couple leaders in the group pooled some money to buy some new terrain, and then had the worst behaved players paint it.
That one day changed the entire attitude of the store, now 20 years later the store has a nice collection of terrain and everyone takes care of it.