Some interesting ideas. Although, I’m not so sure about the tiered payment system as part of the problem as actually attracting paying members to the platform in the first place.
I think the first thing they need to do is make it mandatory for authors to be paying members before they can earn any money from the platform. As it is, more and more authors who don’t have a paid membership are joining the program and earning money. This needs to stop. If you don’t contribute to the pool we all earn from you shouldn’t benefit from it.
Second, it is far too easy to get around the paywall and read as many articles as you like for free. It needs to be fixed as in it’s current form the pywall is pointless.
Third, the platform needs to bite the bullet and allow some limited advertising. Ads could be added to articles read by people outside the improved paywall and provide an increased income stream. This income could then be used to pay authors these non-member reads that currently don’t earn anything.
By allowing authors to earn from outside reads, you also give authors more incentive to promote their work. As it stands, there is next to no incentive to promote your work to the wider community, as all you get is a bunch on non-member reads that don’t earn anything.
Lastly, the platform operators need to have a look at Mediums own publications to improve their appeal, as having professional publications on the platform that appeal to mainstream readers is the best way to attract new paying members.