It's saying a lot about the creator too, since they were unwilling to get unique assets for their game, it sends the message to me, chances are, they were unlikely to get rid of the clunky default RPG Maker mechanics too. It shows a lack of care and personal touch for their project.
I'd say it can be the opposite.
If your game only has less than 10k budget, you can use the budget to
1)Pay for programmer for better/more unique game mechanics.
2)Pay for yourself(the designer) for better game design. Or even hire designers to handle systems that you are not familiar with.
3)Pay for testers to fix more bugs.
4)Pay for an editor to fix bad writing and grammars.
investing your money in any of these above makes your game much better, as well as more "personal touch" than generic RM game in custom assets. But investing this little money on art assets get you crappy assets that isn't necessarily better than RTP.
I've seen more than enough people that asks for custom assets for an entire game for $3000-$4000. I told them thats not enough to create professional looking assets for an entire game with this little money, then they just look somewhere else. They ended up getting assets done somewhere cheap and guess what...it looks bad.
Many commercial asset packs out there are cheap, but it doesn't solve the problem. Most asset packs dont cover all the themes in the same style. If I want to build a game with varied landscapes like having fantasy town, fantasy city, snowy town, fire cavern, 2 different forests and modern city all in one game I'm screwed with asset packs. Since most asset packs only cover 1 or a few themes. I have yet to find any asset packs that is as versatile as RTP.
Mix and match assets from different packs isn't an option. Since different asset uses different color palette, as soon as you mix and match them it's instantly recognizable.
Finally, RTP has the most "additional resources" available on this forum. If you need random add-on like animals, small items, ships you can use them without having to worry about size and color palette. Asset packs are screwed. Trying to add those add-on items and animals to different asset packs won't look good because they are designed for RTP.
I'd only consider all custom assets if I have a much higher budget, or if I'm building a smaller project with just a few locations. Otherwise spending the precious time and money on things actually matter(game design, balance, QA, writing) will get you a much better game than spending all your money on low quality assets.
Ironically, if I have a much higher budget for custom assets Id probably use a different engine like Unity instead.
I may be biased, but I personally feel that community's endless obsession with "custom assets" is the main reason why many RM project has bad reputation: they get the priority wrong.