Can't really come to a conclusion without the numbers to see first. Anyone know the hp values of a mortar and demolition tactic?
Looking at the wiki at least I can pull some hp values off mortars. So let's see. (Also the guys on the wiki have the hp values wrong for the IA and Global Age mortar's original hp. Someone forgot the first 10% hp library tech bonus.)
Demolition tactic with its tactics damage bonus off library gets a 10% additional damage bonus. So at lvl 3 (Industrial) it will do 2000 damage normally, 2,200 damage with the library tech, and then 2,400 damage with the additional 10% bonus off Suleiman if my math is correct.
Now mortars without any blessings, university, or embassy bonuses get a 20% hp increase off library. So an Enlightenment age mortar that is one age down from IA will have 1,820 natural hp, and 2184 hp with library bonuses.
So as we can see here off IA alone if you have only library tech bonus then demolition will deal the about 20 damage more necessary to kill an EA upgraded mortar that's hp isn't being any more influenced by other hp multipliers.
Now WITH university hp multipliers we will have an EA mortar that will have hp increase increments of:
lvl 1 DaVinci = 23% = 2238.6 (If the math is sound then that means just even having one lvl of hp research makes it so 2200 damage demolition cannot kill an ea mortar, this makes it so even 1! point into DaVinci's hp research is a value point!)
lvl 2 DaVinci = 26% = 2293.2
lvl 3 DaVinci = 29% = 2347.8
lvl 4 DaVinci = 32% = 2402.4 ***
lvl 5 DaVinci = 35% = 2457
lvl 6 DaVinci = 38% = 2511.6
lvl 7 DaVinci = 41% = 2566.2
lvl 8 DaVinci = 44% = 2620.8
lvl 9 DaVinci = 47% = 2675.4
lvl 10 DaVinci = 50% more hp! = 2730
Now let's look at the damage increase increment of IA demolition with Suleiman's bonus:
lvl 1 Sully = 11% = 2222 (Can't even kill a lvl 1 DaVinci buffed mortar. DaVinci lvl 1 hp looks more and more like a mega value point.)
lvl 2 Sully = 12% = 2244 (Can now kill lvl 1 DaVinci buffed mortar (Only))
lvl 3 Sully = 13% = 2266 (Still can't kill lvl 2.)
lvl 4 Sully = 14% = 2288 (Still can't kill lvl 2.)
lvl 5 Sully = 15% = 2310 (Can now kill lvl 2 DaVinci mortar.)
lvl 6 Sully = 16% = 2332
lvl 7 Sully = 17% = 2354 (Kills lvl 3.)
lvl 8 Sully = 18% = 2376
lvl 9 Sully = 19% = 2398
lvl 19 Sully = 20% = 2400 ***
The conclusion just based of IA demolition to an Enlightenment age's mortar is that at lvl 4's DaVinci research point that a lvl 10 Suleiman and library buffed Demolition tactic can never kill a mortar in one tactic without Mongols, and since mongols is war only this means that in matchmaking your mortars gain an advantage against people who use that tactic in raids. EA bases still get crushed under air troops though.
I'm sure this information would be more interesting to the folk at global age, but considering a current age demolition against a current age mortar has never been able to destroy a mortar the math isn't particularly important to know. Mongols (and by effect Egyptians as a counter if you see your enemies going for them) seems like the necessity to ever think about using Demolition to kill mortars in a future where everyone has atleast lvl 5 DaVinci hp% increase. I'm sure there is more math that can be done on Mongols hp increase against a mortar buffed by uni and or egyptians. I think I will just take a look at the numbers and see what the results are.
Global Age natural Mortar building hp = 2296.6
With library 20% = 2756
With lvl10 DaVinci = 3444.9 hp
Global Age natural Demolition tactic damage = 2330
With library 10% = 2,563
With lvl10 Sully = 2796 damage
About 648 more hp than the tactic's damage. You global age guys might as well invest in more sabotage or defense tactic. Of interesting note the 2796 damage means you can only kill an IA mortar if it has less than DaVinci's lvl 4 hp research. As IA mortar's hp at lvl 4 DaVinci + Library hp bonus = 2798.4 hp.
If anything though the real conclusion here has been that having atleast lvl 4 DaVinci research on hp makes your mortars have enough hp to essentially counter act a demolition tactic up to the current game's patch metagame as of August 21st, 2016. Suleiman or not, sans Mongols or Egyptians matchups.
You won't even know either. But given that lvl 4 hp research doesn't take much than a month (about ten or more days at the least) I'd say to assume everyone in about a month or two from now will have it and not to invest in bringing along a demolition unless you have Mongols coalition.