The fact that Relay can stay free of charge while "exploring subscription options" means Reddit modified their terms with some developers. The original deal announced at the end of May meant devs would incur charges starting July 1, although they wouldn't have to pay for those charges until August. That would mean racking up potentially millions in costs right away.
Reddit said they would work with developers who kept communication open, but then they wouldn't answer emails. If a deal was made with Relay it would have been very last minute and therefore rather unprofessional.
I used Relay but will not reinstall because it is temporarily free. I am done with Reddit. They don't respect their users or recognize where their value derives from.