Bitcoin mining difficulty has been increasing and will continue to increase:

live chart here:
https://www.coinwarz.com/mining/bitcoin/difficulty-chartI don't see any reason why it would decrease. It's the best money ever invented, so it makes sense that more and more miners are interested in it over time.
You mentioned graphic cards, so I guess you're referring to mining alt coins. In that case this should be moved to the appropriate section of the forum.
I think it's also worth mentioning the ASIC miners on the BTC blockchain continue to get faster and are readily available.
Hell Bitmain is now selling a 100TH miner for $1900 plus 25% customs charge for those in the US.