I'm not sure how it was on previous tiers, but now after 11 weeks of Antorus the majority of heroic/mythic raiders have just 1-3 actual titanforged gear pieces equipped (not counting the 960 gear from weekly chest because that's a different system). Having 5 or more is still very rare even in the top guilds.
Yeah some people are more lucky than others, but for majority the titanforging doesn't make higher level raid loot useless. More often the problem is wrong stats or having a legendary/tier in the same slot. Sure if you farm only heroic for 5 months you may have few more, but this is intented catch-up mechanic and a mythic raider would still have much higher gear.
The main problem with titanforging is the perception and people vastly overestimating the overall effect. But the same is true for all the gearing. For example if you upgrade 910 arcanocrystal into 960, which is extremely rare, the overall dps gain is only about 2%.