This 'constant utilisation' LCC mantra is a bit overstated and most will start early in the morning and finish late at night, as that's when people want to fly! Charter airlines will do the odd night time IBZ / PMI / CFU / PFO in summer but this is an exception rather than a rule.
If aircraft were doing 16 hours and 8 cycles a day you're ragging the aircraft and increasing your maintenance costs massively (the engines especially), as well as not allowing yourself any sort of buffer for delays. Anecdotally, at their base, Ryanair turnaround times appear to be longer than easyJet's; it is just downroute where they try and do it within 25 minutes. easyJet cancelled 100s of flights this summer ex-LGW due to weather / ATC delays. Ryanair at least allow a bit of time back at base to catch up, which is wise.
Most airlines, not just LCCs are doing 10-11 FH / 3-4 FC a day on average in summer on their narrowbody fleet and probably averaging 8-9 FH / 2-3 FC in winter. Over a year, a narrowbody will be doing 2250-2500 FH / 700-1200 FC per annum, but this can vary massively by route profile.
Emirates actually do the most hours in any one day on average globally per aircraft.