I always think salad takes ages to make, the MN massive salad crew must spend their entire lives chopping things 
But I suppose one compromise could be to make an easier sandwich, soup or leftovers most of the time, also batch cook brownies and take supermarket alternatives for crisps, yogurts, pastries (frozen to heat up each day, air fryers are brilliant for this) etc which are far more expensive in Pret etc.
Then once a week or so, buy lunch but make sure it's something that's worth it, ie not something like a cream cheese and smoked salmon bagel, that you can make at home in seconds.
If anyone needs any extra encouragement, I got a really nice insulated lunch bag from TK Maxx, that came with its own Massive Salad tub.
I usually take packed lunch (mostly leftovers, or often batch cooked soup, maybe salad with cous cous or pasta, but rarely sandwiches), because I'm really bad at choosing when faced with a fridge full of choice and I hate fridge cold food so don't want any of it if I'm at the point of needing to buy and eat it now and I've not had chance to get it earlier in the day.
Plus a lot if what's on offer isn't that great and I can make as good if not better myself and the nice stuff that I actually like is expensive so, while I have a decent disposable income, I'm not so well off that I can afford to spend that amount regularly without thought because that would take too big a chunk of my 'non essentials' budget.