'i just wanted to understand if there was now any difference between Lo-cost carriers and standard scheduled services'
I dont understand what this 'now' is, easyjet for example have been scheduled since day one, i.e they run to a timetable just like BA etc does, and have advertised themselves as scheduled since day one. The only misunderstanding, with respect, is yours.
'Apart from operating on a regular basis (some of the time)'.. well interestingly I have flown with both Ryanair and easyJet six times very recently, and I'm due to do three more trips before the end of this month. The only delay I've had (1 hour), was with Ryanair, and that was due to weather which was out of their control. I suspect you don't fly on them regularly, hence your ill informed comment above. All of my trips have been out and back to meetings on the same day! I can do these trips due to the fact that the frequency of their Schedules allow me to do these trips on a single day. If they, loco's, were as bad as your comment implies, then people wouldnt waste their time with them, and they wouldn't survive, its that simple.