I would endorse this position at very least directionally. The job is going to move up the abstraction stack; one person will do what a 5-person startup did, which means a founder must own more product and sales stuff.
If you like working in software because you enjoy writing code, I predict you’re gonna find it harder to make this pay. (Though leisure coding will likely get more fun, and there will always be niche CS-type roles that require inventing new technical systems.)
If you like software because you enjoy making things that people find valuable or entertaining, then I think you’ll do just fine.