If you haven't heard about it, Adobe / Allegorithmic removed the ability to buy a perpetual license of the Substance softwares from their website. It is now subscription only.
It didn't even take them a year to get rid of perpetual. So that's what they call "not for the foreseeable future". I'm not really surprised this happened, but I'm still disappointed. Perpetual is still available via Steam, but I highly doubt that this will stay up for long.
As by their forum announcement here's a couple of details:
Starting November 2019, Substance Alchemist will be officially launched at the end of its beta-phase, and automatically added to your Substance subscription at no additional cost. Furthermore, perpetual licenses will not be sold through our substance3D.com website anymore. However, you will be able to renew your maintenance until October 31, 2020.
Pricing remains the same for the Substance Indie monthly subscription and Substance Pro subscription. Indie annual subscription price will decrease starting November 2019, from $239 to $219.
Starting November 2019, perpetual licenses will not be sold through the substance3D.com website anymore. You can still purchase perpetual Indie licenses for Substance Painter and Substance Designer through Steam.
Further details here.