I was literally having this discussion with some fellow creators yesterday! (And most of our one-star reviews on Born Sexy Tomorrow are from people upset that they have to pay for content.)
Most people do webcomics as a hobby, which I think is wonderful. But if your goal is to become a professional creator, then getting people used to the idea of paying for comics is beneficial for all creators, and the future of the industry as a whole. When people see comics as something that has real value, not only does this allow you to make money off your creation, it legitimizes what we do as something valid and worthwhile.
When Archia (my partner, the artist) and I started out making comics, we were happy to make them for free, and then self-publishing a print version that people could purchase from us. This meant we had to handle printing costs, packaging, and shipping and handling all on our own. It was a LOT of work! It also meant that whenever we were working on making the comic, there was no money coming in from book sales. Archia is a full-time artist, and in order to make money during those lean months, she had to manage a patreon as well as do commissions on the side, which obviously took time away from making the comic itself.
When we got chosen for the first Incubator class, it was a dream come true. The money that Tapas invested into us allowed us to focus completely on creating BST, and something that had once seemed impossible for us - making a career in comics - was suddenly viable!
Tapas itself is a small start-up company (I know it doesn't seem that way when we're using this site) but in order to pay creators, to pay for hosting, to maintain the site, to continue to update and improve user experience, as well as to market to bring in new readers - they depend on ad revenue and Premium comics. When readers pay for Premium comics, it actually goes towards benefiting all of us.
We did a warning on BST before it was locked, and I think a lot of our readers appreciated that. Also, despite being a Premium comic, our subscriber count continues to grow every time we update! Of course it won't be the rapid growth we'd see on a free comic, but as everyone else has said, the readers you lose would never have paid in the first place, whereas the ones that return again and again are your true and loyal fans.I'm incredibly grateful for them because without them, we literally couldn't do this.
As to your biggest question - we do try and advertise on social media (I'm still not very good at consistent updates, I'm struggling to get better at it). I post behind-the-scenes exclusives, world-building extras, select single panels, and I'm starting to do WiPs. However, our social media following is still quite small, especially compared to other artists. And managing social media is a lot of work in itself, so we're thankful that Tapas does feature its Premium content and take care of a lot of advertising for us.
It's actually a very exciting time to be in webcomics! Print media sales are declining in all published industries, and the cost of printing is rising due to paper mills closing (at least in the West - and I know this since we get updates from the printers that we use.) More and more we turn to the internet for entertainment. South Korea invented the webtoon (specifically, the vertical scroll format of webcomic) and it's become a MASSIVE industry there over the last decade. Webtoons are seen as a new media and their own form of entertainment - and they go on to inspire animations, movies, live-action dramas, novels, etc. (And the reason why Naver is investing so much money into LINE Webtoon in the West) If we want to see even a fraction of that kind of success in the English-speaking world, we have to convince audiences that webcomics are legitimate and have monetary value.