OK.. so a few points here.
1. The ridership of metro or uber/lyft is irrelevant to me. The government is deciding to tax one in order to pay for theirs. That's government in a nutshell - tax sucess and subsidize failure
2. I can't find data of ride-sharing in DC either, but I feel comfortable we can use national trends to understand that at a minimum, growth in ride-sharing is soaring. Of course the metro would suffer from this
3. The metro is a city embarrassment... and their ridership is declining rapidly.
That second sentence - specifically about weekend ridership, is heavily due to ride sharing. Also - I can't find any data posted but they are already acknowledging that 2019 is worse than last year
From WTOP last year
Metro has additionally raised prices on fares as well as parking, which I'll project is adding to declining ridership
But after reading your post and looking at more data, I'm not sure what you're quibbling about. Nobody is saying that ride share can outright replace metro, but it is eating into the business, according to metro itself. So, what does the government do? It penalizes the successful service that customers love, in favor of subsidizing the service that customers hate. That is bad economics, in my opinion.