There is a particular process that could be greatly improved, but the person that's making the decision on my proposal will have to apply a little more attention to a particular task. He doesn't want

If this person's boss has a good work ethic, you can escalate the issue. If the boss is a slacker like the subordinate, then you're probably wasting your time.
It sounds like you're in an organization that's poorly managed. If you insist on maintaining high standards and doing the right thing in such an environment you'll be the oddity, and you might get yourself fired as a result. You'll be morally in the right, but you'll still be unemployed. Just something to keep in mind as you consider how much to push things.

if you can sell the benefits of the process improvement then they should at least listen to you.

All you do is to solve problems. Problem is a gap between perceived reality and desire reality. You have to work on that. Is about your clients perception. If they think something add cost (not monetary only) to their work life then it will be not motivated to work.

If "Putting extra effort" is the actual reason, ask him would he approve if one of the team member can put that extra effort(like surrogate access) for sometime until we get results and give your boss all the Credit and say i own if it fails. Once you start seeing the results you may sell this proposal/idea to your boss or next level easily.

Be sure about his actual concern. If its not the "cost/fund/budget" then you should be able to convince him with above approach.

Power of influence. Are you bringing him clearly to the water to drink? Have you set a clear path for him to see the same benefit you see in this added work?

The way you explain sounds to me like he doesn’t see the value first. I don’t think it’s much concern with an added hour per week.

The same holds true in sales. The most common objective to not closing deals is the customer says it’s too expensive. I’ve found not only in personal situations, but through observing that this is false. If you deliver the value in such a way and hit them with a solution that fits their pain point, their need- people are willing to spend more money than they anticipate.

Speak with conviction and provide the solution to the exact problem and others will follow. Maybe sit down again and analyze your proposal. How can you tweak it to keep the benefits but change the focus maybe in order to show its value to the process? What is your approach? Do you speak with full conviction and belief or do you come off slightly hesitant or lacking confidence that this very proposal will provide great value to this section of the project?

Maybe instead of going behind this personas back to escalate it, use both stakeholders to revisit this proposal in a joint meeting.. bring this person and his boss in to a meeting with a clear objective and a precise time frame to discuss. See if you can influence his boss which in turn will start a debate conversation between them. Maybe his boss can change his perspective or agree to sign off on this proposal. This is a chess game of influence.

I suggest making some small changes if there areas to alter and pull them aside to set up a meeting. Maybe you can make a small change that won’t add an hour per say, maybe it’ll just add 30 min per week.

Hi Bruce - First address his concerns - maybe tweak your process or accommodate his concerns. Next give him and his boss the presentation of cost-benefit analysis and let them take a call. Use 'Dale Carnegie' principles to woo them. :)

WIIFM. Is this improvement just for the sake of improvement? Does the benefit outweigh the cost? Are you asking someone to change who sees no significant benefit to himself or the company from the change?

Before you go to his boss, determine if the benefit from the change will be worth the potential damage to your relationship capital with the individual AND his boss. If the benefit is significant, the risk becomes more worth it. If the benefit is negligible, it might be worth it to accept his denial and share your reason with the individual so that he is more likely to recognize that you are trying to do what's best for the company and not just pursuing your own agenda.

I agree with Eric on this.
When you see someone that's not paying attention to your concerns, I think that's a sure sign that you should take your concerns to their boss.