Astronomer here! Believe it or not, there is actually significant concern that this will make astronomy much less accessible as a field. Two important reasons:

• The big journal run by the Royal Astronomical Society is the Monthly Notices of the Royal Astronomical Society (MNRAS)- it has traditionally been a very important journal because unlike pretty much any other, it was free to publish in it. Obviously cool for obvious reasons, and meant researchers at less prestigious universities with less funding for these sorts of things would still be able to publish in a great journal (and MNRAS picked up the tab by having subscription charges to universities). Now, however, this means it'll be 2310 GBP (~$2700 US) to publish in MNRAS- a huge barrier for some institutes. They say there are going to be fee waivers, and authors from certain countries don't have to pay... but trust me, there are astronomers on more bare bones budgets in other countries where having "pay to play" to get your science out is going to be a hardship. :(

• Meanwhile, it is worth noting that astronomy has been open access since the 1990s! Pretty much everything goes on ArXiv.org when it's submitted/published, and older papers are available via the Astrophysical Data System (ADS), which is kinda what Google Scholar is for other science fields but leagues better. So it's not like anyone in astronomy has been hurting for a lack of access to MNRAS.

So, why is this happening? Well right now there is a push by science governmental organizations to have open access journals. I'm not knocking this at all, mind- it does seem ridiculous that the taxpayer has to pay for access- but my point is astronomy is the field that actually solved this decades ago. And, in practice, guess who's paying all those paper charges? The taxpayer, of course- it's just now in a way where it's bundled into grants, and makes the field less equitable in terms of who can afford to publish. Think of it this way- if you have a PhD student and X amount to spend on them, this is now going to mean that student will be attending one or two fewer conferences during their career for doing the same bare minimum of getting published (because I guarantee you that research grant sure ain't going up).

Mind, I don't know if MNRAS had much choice in this decision. But my point is, this is far more complicated than meets the eye from this initial press release.