I doubt they are dropping ST1 production, it is hard enough to sell a 4 thousand dollar bike let alone a 7 or 8 thousand model. They may even be required to support the product for 7 years IIRC. Third party replacements/rebuilds are also likely IMO. -S
More likely that the ST2 design would be terminated before the ST1.
I bought a Stromer closeout last year and very happy with it. Not worried in the least about batteries or motors/controllers etc.
I can't imagine BMC, who owns Stromer, would leave their ST1 owners stranded by abandoning the spare parts inventory... Unless they decided to give up on eBikes altogether. Then they would sell the brand to someone else.