Is The drop rate for revives from the pokestop reduced?

same with me, some weeks ago in a 1 hour car ride i could get 100~150 pokeballs and 50~60 revives, now a usually get 50~70 poekballs and 10~20 revives however now i get tons of potions instead

Based on the drop logs available, Gamepress estimates that revive drop rate has decreased about 25% since the 0.35.0 patch. This was exacerbated by the update also made revives a requirement for Pokemon defeated from training or kicked from gyms.

You can see more information on the datasets collected in the Pokestop guide:

https://pokemongo.gamepress.gg/pokestops

and this thread:

https://www.reddit.com/r/TheSilphRoad/comments/525uls/pokestop_item_drop_calculation_august_21st/d7hwsog

My only advice is to change your gameplay style. If you're good about swapping out your attacking pokemon when they're low on HP (and running away from a battle if all 6 of your pokemon are low on HP), you should be able to fight gyms without ever needing a revive. The only thing I use revives for anymore is for my defending pokemon that get kicked out of gyms.