It used to be that if you wanted a higher quality, you had to find a quality brand you could trust, and if the market doesn't favor lots of competition for whatever reason, a quality brand just wouldn't exist without government intervention. After all, why would a rational profit-seeking corporation do anything right if it put them at a cost disadvantage
The only reason you might not be able to find something of higher-quality is because not enough others want it. Internet or not, if demand exists, it will be fulfilled — glory be to our Free Market (whatever is left of it).
Internet may be making the market more efficient by facilitating information exchange, but it is not required. Nissan created Infinity and Toyota — Lexus before there was Internet. Cognacs are available in different (standardized) quality-levels — and have been since 1800-eds, when even telephone did not exist.
The taxi market is traditionally so monopolistic that the only way to make good quality available is to legally require it from everyone
It is monopolistic, because there are virtually no repeat customers — even if you really liked the guy, who last drove you, you will not be waiting for him, when you need a cab again. You'll just hail whoever drives by. The tips are supposed to compensate for this absence of incentive, but aren't doing it, because many people tip — out of politeness — regardless of the service-quality.
But you are right that the feedback forums — which can make or kill a particular maker/seller/service-provider — are changing everything. For the better.