Because Roger Ver is among those a few people that really understand bitcoin's potential. Programmers seldom look away from their technical worries, they care about how the car works, but are not able to see where the car is going
The blocksize debate is not a technical issue, it exposed several long existing problem of bitcoin: Mining centralization, development centralization and lack of consensus based decision making mechanism regarding protocol change. And what core programmer is doing is to make these problems worse, their solutions create more and more centralization incentive, especially in R&D. If bitcoin is centralized in the hands of a few guys, government and law enforcement will take down them in a couple of hours, then the whole system will just collapse like e-gold or liberty reserve
bitcoin is the first and only crypto that has face this problem because is and the most popular. To find a proper solution for a tech problem you need someone who really understand how the tech works and not a manager or a marketing guy.
It is this mindset created current mess. There are various of ways to solve a technical problem, if you could not find the way that align with your long term social economy goal, it just means that you are not smart enough and not qualified. By changing the long term goal to suit a narrow technical limitation is like driving a car into the river because your steering wheel is locked: You have to sit in the car because it is high-tech
Just look at how Windows took over nearly most of the desktop market, they had far less stable and secure technology comparing with unix system at that time, especially the network part, but they get the right market direction before any other tech gurus realized it, they patch each bug, patch after patch, but their direction never changed: End user friendly
Similarly here, by putting all the transactions on-chain, you have to strive to find the best possible on-chain scaling technology, like thin blocks doing right now. But if you start to become lazy and try to use the old centralized financial models like payment channels because they can provide millions of transactions per second, then you just drag bitcoin into the old banking model, which will dramatically reduce its usage and increase its risk, especially when there are many other alt-coins provide on-chain scaling