Product differentiation != new features.
New features can enhance differentiation, but these are not the same thing. For example, product differentiation can be predominantly delivered in the go-to-market if a product's "see-try-buy" motion is just inherently better than everything else available. The differentiation there is in the trial experience and ease of transaction - not necessarily in the latest feature.
Don’t forget about marketing, positioning and acquisition of customers as a key part in your differentiation strategy.
It’s easy for Product Managers to solely focus on the bits and bytes of how the product works once someone’s in it, but if you cannot acquire or entice new customers - you need to move your differentiation focus further up the funnel.
Is your product too hard to set up or use? Does it take a long time for users to see value in your product?
It’s key to partner with sales, product marketing, support and solution engineering to get the full picture here.
I'll keep this one rather brief.
I find that some product managers do not always listen to their customers and their problems as the guiding light for improving and differentiating their products. Instead, they fall in love with a shiny new piece of technology that may not be solving a critical problem.
If your exec team has not articulated a credible product strategy it could be that they don't know how or they feel that they cannot invest at this time due to much bigger near term issues or constraints. Consider what that might be saying about the viability of the company either way, and a potential switch. If you are still compelled, one way is to try using the voice of the customer: ie compile direct feedback on where your customers want to see your company go to continue being customers and couple this with a competitive strategy comparison.
While it may be tempting to get sucked into feature by feature wars and spar through marketing communications it will not yield much for whoever (you or the competito) lacks sources of Sustainable Competitive Advantage. see related answer on what those are, not to be confused with Competitive Advantages