Full blocks is a change to how Bitcoin has been run. The limit was always meant to be raised as it was introduced as a spam protection. The full blocks policy has not had any research backing it at all.

No, it's really not. It was there from the beginning. Satoshi himself put it in place, years before blocks got even close to that size. When other people wanted to lift the limit he argued against it. He clearly did not deem it important enough to even research what limit was appropriate.

There's also the fact that Satoshi put a pretty agreesive schedule for the deflationary aspect of Bitcoin. Fees were designed to gradually take over as the miner's reward. You and I may or may not agree with that policy, or the schedule it follows, but it is a policy that was designed in from the beginning.

You're confusing the limit with full blocks. For all good it did the limit could just as well not have existed since blocks never reached it.

Furthermore Bitcoin used a soft limit which miners themselves increased. This is now no longer possible.

Satoshi introduced the limit as spam protection and he also explained how it could be phased in using a hard fork (although the term was coined at a later date).

I quote:

It can be phased in, like:

if (blocknumber > 115000) maxblocksize = largerlimit

It can start being in versions way ahead, so by the time it reaches that block number and goes into effect, the older versions that don't have it are already obsolete.

When we're near the cutoff block number, I can put an alert to old versions to make sure they know they have to upgrade.