This is completely empty and made up argument. For every piece of software with perpetual license you can normally get evaluation version. Download and evaluate to your heart's content. Normally it is 30 days but I have not had one case in my live when vendor refused to extend eval period when asked.
If he doesn't think you're worth the money... You can say gravity is wrong all you want, you're still hitting the floor.
He wants a different product with features that aren't in the MVP. He absolutely is not the person I'd be selling to. If it turns out that I can't find customers selling what I think is the right product for the market then I might have to pivot to build what he wants, but until then he's just someone who isn't my potential market right now.
Startup sales is about getting the customer to buy in before the product is exactly right for them. Changing your product to suit whatever the person in front of you wants is massively distracting, often bad for the product, and doesn't guarantee a sale anyway.
If he doesn't think you're worth the money..
The product not being what someone wants only means it's not worth the money for them. That doesn't mean the product isn't worth it for anyone. You need to find the person who wants what you have right now despite it not being perfect, and who is willing to pay for what you have on the basis that it'll become what they need in the future.
No one should be worried about perpetual licenses or offline support for an app that hasn't proven it even solves the problem in a viable way yet. If those things are key to your purchasing decision then you probably ought to be buying from established businesses with proven products and good support, and that is definitely not any startup I know.
I suspect your comment betrays the fact that you think the first version of a startup's software is the first finished and stable version. That's the main problem here. Startups need to be selling long before they're at that stage.