Thermodynamics are the reason why SMR aren't, and will never, be economical. A bigger nuclear reactor will always undercut your price per watt.
The fact that we haven't seen more widespread use of SMRs suggests that you're right. But it's important to point out that there are cost saving opportunities that could potentially reduce the net price per watt despite worse thermodynamic efficiency.
The additional per-site engineering required to reuse things like turbines and dynamos is almost certainly going to kill any savings it would have. If you're already shipping a building-sized reactor, what's one more turbine? Realistically the main reusable component is the grid hookup itself - but that would incentivize building a large-scale reactor on the site.
As would reusing the turbines, for that matter: you can't exactly power the turbines of a 100MW coal plant with a 10MW reactor, and shipping ten inefficient 10MW reactors to the site just so you can reuse the existing ancient turbine isn't exactly an attractive option either.
And the link between thermodynamics and the price of electricity is what?
Sure, that is economics, not thermodynamics. I don't necessarily agree with the SMR manifesto, but it is conceivable that improved financing, construction, operation and oversight could make an SMR cheaper than a larger reactor.
You do need to have unreasonable goals for things once in a while. In this case, I don't have a particularly fixed stance about SMR's, but the claim that "Thermodynamics are the reason why SMR aren't, and will never, be economical" feels a bit stronger than it is warranted. Never is a damn' looooong time. And I can easily imagine things being less efficient, but having other advantages that make them more economical. Claiming it's impossible is just stretching.