Thats the main goal imo. Theyre not teying to compete with the high end devices, all of them will likely download steam and give Valve money anyways. Valve always targets on expanding the market, with vr and such. The Steam Deck exists to expand the market to budget pc console like gaming, and it would not make sense to replace it now.
Valve I dont believe sees it like a cellphone where theyre trying to make more money by doing yearly releases. They arent a hardware company fundamentally. They only develop hardware as a means to expand market, not to make profit directly off of.
Its why virtually none of their hardware projects are bog standard, be it steam machine/deck(Linux market), index/vive (VR), Controller (touchpad, HD Rumble), Link(local streaming) as each project was designed to introduce pc gaming to a new market, or expand pc gaming by adding new features