I agree that this tweet is elitist. I am doing my Ph.D. in a 50-60 ranked program which PSB would probably call third-tier. Except for one person in the last 10 years, all of them Ph.D. graduates have jobs. Of course, these jobs are not like a tenure-track job at Harvard or Princeton as there is no way we can place that high but they are either employed in the private sector (think consulting, data science) or in small colleges or big directional schools.
I do not support closing down these programs but they can decrease the number of people admitted which is relatively low anyway. Harvard accepts 20-25 Ph.D. students per year in political science while my school and similarly ranked schools accept around 5-6. My cohort is 5 people while a cohort below me is 4 people. Instead of attacking lower-ranked schools, we can talk about the real problem: middle-ranked schools who think they are Harvard so accepts 15-20 students per year.