You make no point other than your inability/unwillingness to use a search engine.
Actually I did make point. You just failed to grasp it.
How come the Russians were never able to destroy the Fins on the ground? airfields out of range?
Well Soviets did manage destroy planes on ground (regarding Brewster the most notable case was raid on Immola airbase 2nd of July '44 where three Brewsters were destroyed on the ground) on couple of occasions but strafing airfields won't really cripple a whole air force. Also Karelian region had quite a few (see Karelia terrain in AH) remote air bases. When aerial attacks started to become more frequent, a base could be changed and planes were kept well hidden in the out skirts of the airfield in the woods. That way planes were harder to target from the air and squadron was free of attacks until Soviets figured where they had moved this time.

During the Winter war several iced lakes were used in this manner.
A random sample of kills by LLv26's Brewsters:
17.06.44, 16.45-17.45, P-39
17.06.44, 17.20-17.25, Pe-2
18.06.44, 07.45-09.05, La-5
18.06.44, 07.45-09.05, Pe-2
18.06.44, 07.45-09.05, Pe-2
18.06.44, 10.50-11.30, La-5
14.07.44, 15.15-16.50, Yak-9
14.07.44, 16.00-16.30, Yak-9
15.07.44, 11.35-12.55, LaGG-3
16.07.44, 13.10, La-5
16.07.44, 13.17, La-5
27.08.44, 09.30-11.15, P-40
...this is the reason why it is getting a bit tiring to hear that "Brewsters only faced I-153s and I-16s".
During the summer of '44 Brewsters scored 17 kills while losing 2* aircraft in combat themselves (source: LeR 3 by Keskinen & Stenman).
*Wanted to correct myself. The actual number is four instead of two. The error was caused by the list of loss reports which ended to 20th of July '44. I double checked the number from Jukka Raunio's book but he had made the same error. Jaakko Hyvönen has written an excellent book which lists all the FiAF losses where an aircraft was completely lost or cases where someone had parachuted. It mentions the other two Brewster losses on 29th and 30th of July. So four is the correct total for LLv26's Brewster losses in combat. Doesn't change the fact that an exchange ratio of little over four is hardly
"getting one's butt kicked".