It's not because of just this event. It only gets worse from here. If you aren't a whale, they don't care about you.
Well, if you don't spend money on the game, you're not really a customer.
On the actual topic of the boss fight, I have yet to try it. While I have bought Lapis. I have yet to use any of that Lapis I've purchased. Still 10k+ Lapis away my amazon purchase. So I'm still in the F2P range.
But I'll give my two cents.
1. This trial has been out for less than 10 hours. Most complaints don't even make sense to me right now. It would be akin to playing an MMO and expecting to clear the new raid the day it comes out.
2. That is how all RPGs progress, those who invest more into will be ahead of the curve. In this case, rather than the typical MMO where time is the most value resource. Money is.
3. This applies to both of the above, within 10 hours of play, you haven't actually made any real adjustments to your team. You haven't had the time. Spend this weekend raising a character if you have them or farming some abilities, etc. The Demonic Life Materia actually could be very good here. Every character will get below 50%, so a free Cheer for the rest of the game is fantastic.
Also, next Thursday will most likely release the rest of the next area. This includes 10% ATK Materia and Carb(I believe he is Light Resistance). Which will make this fight far easier.
Basically, you there is plenty of ways to get some gains over the week. Prep up like Batman.
4. Some people have only been playing a month or two on their account. So of course it's going to be hard. People who switched over to Alts or new players. You don't have the 5-6 months other people do.
Now in defense - This is a limited time trial. So we are all feeling the rush.
But I would largely say instead of throwing Lapis away on pulls this weekend, use it for Refreshes and clear content, Level up if you can, etc. The same goes with energy and attempts. if the first didn't go well, having Refia, Tilith, CoD, Cecil, etc. Someone who can help you a lot at max will be beneficial.
And finally, at the end of the day.... not getting Maxwell won't kill you and there is a good chance he'll be back once he gets his 6* with Part 2 of the FFBF banner. So relax, don't rush it.