* http://jdebp.eu./FGA/dns-srv-record-use-by-clients.html
In reality, the number of back-end DNS queries to perform an A or an AAAA lookup can vary enormously, and can number in the tens or hundreds of queries already. It's not generally true that the number of back-end lookups will increase, because the number of back-end lookups varies wildly by time (depending from what is cached from momement to moment) by domain name (depending from the amount of gluelessness) and by country. There is so much variation in there already that the variation caused by a two-step SRV lookup can quite often be lost in the noise.
Of course, SRV lookups do not even have to be two-step in the first place. A proxy or content DNS server is free to add the requisite A and AAAA resource record sets as additional section data in its response, meaning that the client obtains both pieces of information in a single transaction. And of course several real world DNS server softwares do exactly this.
* https://news.ycombinator.com/item?id=8850302
Whenever you see these objections, always remember that there are protocols where SRV resource records have been in use for coming up to twenty years. And yet one never hears of actual problems with those protocols that mirror the supposed projected problems of using SRV lookups for HTTP. A lot of what one hears about why this would not work is simply bad analysis and excuse making.
The worst part perhaps is that the code to do this for one of the WWW browsers was actually written, the only actual technical niggles were solved 17 years ago, and -- perhaps most tellingly of all -- whilst people are still telling us how this cannot be done all these years after the code was written, there are parts of the world that are quietly and happily doing it right now. The FreeBSD packaging system uses SRV resource records and HTTP/HTTPS, for example. It's also an example of how real world DNS servers can and do send all of the data in one transaction using the additional section. They've even made it in-bailiwick.
JdeBP % dnsq srv _http._tcp.pkg.freebsd.org. ns1.isc-sns.net.
33 _http._tcp.pkg.freebsd.org:
510 bytes, 1+5+3+8 records, response, authoritative, noerror
query: 33 _http._tcp.pkg.freebsd.org
answer: _http._tcp.pkg.freebsd.org 300 SRV 50 10 80 pkg0.isc.freebsd.org
answer: _http._tcp.pkg.freebsd.org 300 SRV 50 10 80 pkg0.nyi.freebsd.org
answer: _http._tcp.pkg.freebsd.org 300 SRV 10 10 80 pkgmir.geo.freebsd.org
answer: _http._tcp.pkg.freebsd.org 300 SRV 50 10 80 pkg0.bme.freebsd.org
answer: _http._tcp.pkg.freebsd.org 300 SRV 50 10 80 pkg0.ydx.freebsd.org
authority: freebsd.org 3600 NS ns1.isc-sns.net
authority: freebsd.org 3600 NS ns3.isc-sns.info
authority: freebsd.org 3600 NS ns2.isc-sns.com
additional: pkg0.bme.freebsd.org 3600 A 213.138.116.73
additional: pkg0.bme.freebsd.org 3600 AAAA 2001:41c8:112:8300:0:0:50:1
additional: pkg0.isc.freebsd.org 3600 A 149.20.1.201
additional: pkg0.isc.freebsd.org 3600 AAAA 2001:4f8:1:11:0:0:50:1
additional: pkg0.nyi.freebsd.org 3600 A 96.47.72.71
additional: pkg0.nyi.freebsd.org 3600 AAAA 2610:1c1:1:606c:0:0:50:1
additional: pkg0.ydx.freebsd.org 3600 A 77.88.40.109
additional: pkg0.ydx.freebsd.org 3600 AAAA 2a02:6b8:b010:1001:0:0:50:1
JdeBP %