Lead acid batteries are indeed wasteful both in discharge due to Peukert Law but also during charging much energy is wasted for example to recharge 1kw/h used will generally take 1.5kw/h there is another problem as battery state of charge increase rate of charge decrease so they only really fully use the panels when they are at 50% dod this is why my system is Hybrid & sends the surplus power to the inverter when batteries are no longer pulling full power from the panels it is also important that the batteries are always fully recharged to avoid Sulfide buildup and capacity loss. (memory effect)
Life cycle wise , Floaded & AGM have very short life 300 cycles maybe… But Deep cycle GEL has long establish high service life many many cycles if Depth of discharge is kept to 50%
I totally agree Lead acid is not the best technology for this application but the cost of large lithium battery bank and all the additional technology needed to charge it safely is still very high
I generally keep my discharge rate to 20H giving a theoretical 45AH per battery assuming a 50% DOD totalled up this gives fully consumable 90AH at 26v (2340 W/h) note that 24v would be fully discharged….
When i built system a few years back the cost of good (3ah high drain) 18650 was 10 bucks each! and i calculated i then needed 220 of them to make up the same 2300 watt hours and to make matter worse cycle life was only 200-500 depending on discharge rate! 
Where as the manufacturer of my Gel batteries quote 2000 cycles with my above setup and gave me a 6 years guarantee 
(I will be counting)
But now you can buy 5ah 26650 from Liitokala for just 3 bucks… Perhaps tables have now turned it really depends on the cycle life
Those Liitokala 3.7V 26800 7200mAh you posted look very good, I wonder if anyone has tested them properly?? if that cycle life & capacity is true then it is certainly a better option and may even work out cheaper than lead acid! I may have to order a few for testing 