Are sales of vinyl records really increasing? Why or why not?

They are increasing yes, but the volume of sales is still minute compared to what it was 30 years ago. No matter what anyone says vinyl record sales account for less than 0.01% of physical music sales, it is wholly dominated by either CDs (in serious decline) or downloads (legal/illegal).
A recent school survey in Hungary discovered that out of 400 students (12-18 yrs) only 2 had bought a physical "disc" of music in the past year and half had no intention of ever buying music, that is, paying for it in any format. Everyone else downloaded their music (torrents or simply copied). The only CDs they had were bought for them by parents or grandparents.