That is just nostalgia talking.
Cricket wasn't even a professional sports in the 70s. The quality and level of the game has gone up several notches since the 90s.
And that is true for any sports where exposure and investments are on an upward curve.
The hitting ability of batsmen, the quality of fielding, the fitness of pacers - everything is better today than it was 20 years ago.
Cricket actually is the first modern game to be professionalized - from 1864. 1871 was the year when County cricket started and it was complete professional league with games in 6 days of week & Sunday off.
But, I get what you are trying to say here. That's true for most other sports, probably every other sports - NOT FOR CRICKET. The reason, this game is completely different from any other modern game. It's learned, developed & mastered through longer format of the game. By nature, cricket is a slow, skilled based game built on mental & physical endurance, and perfection of the skills, which can't be developed without longer game. Today, we are killing the longer game both domestically & Internationally - that skill level will never reach at the highest level. People can't compare that because we can't arrange a game between best of 80s at peak Vs best of 60s or 2010s at peak - you are always watching games between contemporaries.
These power hitting and all sorts of fancy staffs that recent people talks about have very little idea of the game. Today you are watching Gayle, AB or Butler "Power hitting" bowlers - 15-20 years back had they not mastered their batting skills from FC system, they won't have been remotely close to what they are now. I read lots of funny comments regarding Power hitting here in PP - if half of that was true, best power hitter in world should have been Md. Irfan, the 7 footer guy.
Fitness requirements are completely different in cricket - 6 pack Watson is one of the most unfit cricketers ever, while beer belly Shane Warne tormented batsmen for 2 decades, overs after overs, hours after hours, days after days. From modern Gold gym body, any top fast bowlers from 70s - 80s - 90s were much fitter, even more than Kohli. Take Kapil or Imran or Hadlee or Marshall - they used to bowl 1000+ overs in English summer in 5 months, then to their own domestics, International cricket .... add to that Imran or Kapil or Hadlee or Botham putting similar effort in batting - it's 2000+ overs/year & they used to bat as well - between No. 5 to 7..... add to that similar work load at nets.
Fielding standard is worst now in last 35 years - what has improved is athleticism and ground covering, throwing, sliding etc .... Catching is at it's lowest level, not only slip catching, anything that needs sharp reflex or solid grab; what has improved is area coverage for skiers like baseball - still the catching isn't safe; Chahal dropped Liton, Shahzad was dropped against BD. Check replays from 80s & 90s - top fielders used to grab balls at one touch, now most fielders dive in the line of ball to stop it - how many clean pick-ups have you seen in these days like Jhonty, Azhar, Mark, Ponting, Gibbs or Hooper? Least said about catching against spin at close-in is better.
Spin play is at it's lowest standard, probably since WW II. Even Indian batsmen are bunnied by the mighty spin of Moeen Ali!!! These guys Rashed, Mujeeb, Akila are bamboozling batsmen like the biggest mystery on earth - because of non existing footwork & spin reading ability; even Shadab looks a Champion bowling 60% Googly, because most batsmen these days can't read Leggis from delivery release or in flight. 20 years back, you would have seen batsmen taking their front pad just outside line and negotiate his Googly.
The reason why the quality of cricket is declining fast is because of less importance of FC cricket. It's a slow death, we can't help - Millennials won't ever bother for a game that lasts for 4/5 days, and you can't master this game just from hitting hard or bowling fast - it's a skilled based game like Yoga, which needs years long slow learning.
I am too young to be nostalgic about things just 20 years back - but I understand this game a little, how the skills are inter related and what are the success factors. Most importantly, I can compare the skills of the game. No nostalgia here - cricket reached it's peak in between 1980s & 1990s, flanked by 1970s & 2010s - before that it was amateurish staff, after that T20 staff. That's why you'll see me regardless of Nationality, rating top players in those 35 years highest. There are many ancient games that had been erased from modern days, cricket is going to be another one - just not because world in moving forward this game will also move forward.