Yes, if someone cancels a date multiple times, theres no way back. You were right to dump, as it would only be more of the same, so don't degrade yourself by giving him endless chances.
I have asked in the past about their single friends/ relatives, in case they might know anyone to introduce me to, however their response was they don't consider any of the single men they know good enough for me
This sounds as though theres something wrong with you but actually I doubt it. If I wasn't with DH, I would be thinking much the same. I don't think I've met one really nice single man in years. OK, I'm not looking, but nevertheless I've encountered many single men socially, and they have all mainly been putting it politely not relationship material for a decent, well educated woman. Even if you ignore the lack of physical appeal (bald, fat and wrinkled), the unhealthy habits such as excessive drinking and lack of exercise, the lack of well paid job, stable career or home ownership, the inability to spell or even pronounce the English language reasonably accurately, then theres the inability to create an empathy with a member of the opposite sex to consider. And even if you bypass all those faults, theres the ones who are single because they cheat, or are abusive, or are just impossible to live with.
If I was single, I probably wouldn't be attracted to anyone who wasn't a fellow professional and interested in sports, who was of the same standard of looks as myself. Otherwise, you're kind of just forcing yourself to be attracted to someone who is less than ideal for the sake of not being single any more. And there can only be very single few doctors, dentists and lawyers around.
And why are these single older men so arrogant? I've got a bald as a coot odd looking man on my FB right now who is advertising himself as single and keeps sending all his female friends pms in the hope of getting attention getting a shag. From the way he writes, it is obvious he considers himself quite a catch, not least because he owns a small poky flat in a rough part of town! Yet his only hope really is coming across as a nice, decent, modest guy, because cocky, arrogant self obsessed men don't tend to attract nice women.
Even in my twenties when there were more decent single men, finding one was still hard. So in summary OP, no I don't think its you at all, I don't think you should lower your standards and I think if anything the fact you have not paired up with one of these weird and odd creatures is probably a positive sign about you if anything.