I believe that, as far as "The Secret" goes, this is what he always intended. The idea had been floating around forums for quite a while and I have no objections to that.

Having said that, RtMI feels like Ron Gilbert telling me to go away and do something else with my life. The world is falling apart, the game characters don't care, the ending itself gives up on you and, in case you didn't get it, there's a letter afterwards from Ron Gilbert himself telling you that, if you try to recapture the past, "you'll sort of get what [you] want but it won't be what [you] expected".

As far as I'm concerned, I would have preferred it if he hadn't made the game at all.

I thought the ending was lovely as well. We get sincerity, but seems some people can't go to sleep without an epic boss fight and some dramatic reveal of the "secret". This was the better way to do it and for me the best point and click ever made.

He's also been creating absurdist controversial endings to adventure games for a long time before Return to Monkey Island (SoMI2, Thimbleweed Park)...