Mark has no obligation to tour every two or three years this is just that we are used to this scheme.
He hasn't. We are used to this scheme, of course, and that's the only thing we have to speculate
We are not in the writing-recording-touring mode, some extra project has been inserted.
And that's why we are more than speculating, cause this time there are extra factors
Add that some delay can occur for almost any project. This happened with the GH release and the subsequent 1995 planned "His First Solo Tour".
And with the STP release, three film scores (Metroland, Wag the dog and A shot at glory) interfered with the STP recording process and it took four years between the GH tour and STP release.
Last but not least Mark is ageing and may need more time / shorter tour such as doing US fall tour instead of doing both Europe and North America with only a 15 days break or so in between.
Actually he is doing that for the last two tours. First a European tour between Late April/May and July, and then a two months Fall tour in NA.
In my humble opinion, he plays too many gigs during his European tour, too much cities in Germany, Spain, France... usually he played just three or four as much, in the biggest cities, so the older he gets the more gigs he plays, he is doing it the opposite way...
In Spain we were used to have between two and three concerts (Madrid, Barcelona and other town,sometimes Bilbao, others Zaragoza...) but the last three tours he played a minimun of six concerts, usually in towns he never played before...
Whatever, let's hope that September bring us at least, some information to keep speculating and having fun while something happens!