Maybe do more dungeons and Strongholds then, I had luck with those aswell. And dont forget the “get lucky vendor”, I got like 2 legendaries for each 500 spent. I was doing side content until lvl 40, at that point I decided to rush the rest of the campaign as I wanted to go to Tier 3 difficulty to get more of a challange. Now im doing the rest of the side content on Tier 3 (still easy btw).
But as I said, legendaries are not the deal-maker (at least till lvl 50-60, where I am now). You can still do very well with only rares if you care about the item-stats and plan your build properly.