While utility and ergonomics can be debated, I'd be surprised if performance of Google Maps in particular has regressed. Google keeps track of latency metrics for every one of its thousands (millions?) of services. If the services involved in Google Maps began to regress in latency, it would have been noticed and addressed. You can be sure that many performance improvements have been implemented, and if you had access to the 2005 and 2019 versions, you would be amazed at how capable and fast today's is compared to then.