Ok, fair enough, but that is less than 1/1000th of the economic output of the country, based on a year’s worth of action that generally involved Network Rail signallers striking and thus closing a significant part of the network - such that typically on a strike day only around 20% of normal services could run (but usually carrying 30-40% of usual passengers).
Clearly the functioning of the railway does have an effect on the economy, in many places.
My point is that the industrial action occurring now is not having the same impact as it was up to March; with the ASLEF overtime ban the network as a whole is running almost a full service, with passenger numbers barely twitching. When the RMT strike tomorrow, there will be something in the region of 50% of normal services operating, and my educated guess is that somewhere around 70% of usual passengers will be carried. And therefore the economic impact is much reduced compared to what it was, which even then was frankly minimal.