You think a one off CL win would help us close the gap? I could see acquiring some big sponsorship deals, but I can't see it being enough to come near what PL teams get with sponsorship and TV deals combined
If the current trends continue, there is a chance that Juve and even Bayern might be left behind regardless of what Juve or Bayern do. If you assume that the EPL will keep getting substantially richer as a whole, and that this continuous crazy increase in wealth will be reflected in terms of inflating player transfer prices and salaries + eventually in performance on the pitch, then there is a real problem for non-English clubs in the long-run. Clubs like PSG for instance are fucked in the long run because there is no hope for their league at all. All they can do is become better commercially which is tough when you play in a league no one watches. The EPL big boys can grow faster commercially just because people watch their league more often (Arsenal grew tremendously commercially without a single title) and when their wealth is reflected in their players and performances they will eat the commercial market share of PSG who are only followed in the CL.
Bayern have a fighting chance because the Bundesliga management (as well as individual german clubs management) is much better than in Italy. So perhaps they will eventually be able to market their league in a way comparable to the EPL and will get comparable TV deals. Bayern are already monsters commercially and commercial success is their only way of keeping up until the Bundesliga as a whole gets a better TV deal. They have good foundations for that (good management of league and clubs and strong economy and healthy local fanbase and stadiums etc..) but the problem is they have no other powerful brands aside from Bayern and the TV money gets distributed equally over all the clubs so Bayern's cut is small if the TV money is not insane. And the TV money wont become insane where BVB is your only somewhat good brand apart from Bayern. So commercial success is Bayern's main weapon but it might not be enough because EPL top guns can match that too.
Italy's edge is having the highest number of historically giant clubs. So there is potential that this league can become very marketable in the future as a competition and there is good potential for the commercial success of many individual clubs. However the management is as bad as that of the Egyptian League and there are no signs of change. The stadiums are a disgrace. Clubs that can have a big commercial impact are managed by incompetent imbeciles. The italian economy is pathetic and will only get worse etc.. So no infrastructure no economy and horrific management.
Being profitable will not be enough. We will eventually be like comparing a kiosk's profits with a department store's profits. Even if in net terms you are generating the same amount of profits (say 100 mills), The English club will be doing it with a capital that is in the billions while you are doing it with a capital that is in the millions. You can be like profitable like Ajax or Porto without being a top team anymore because your whole company size is much smaller than the big boys who make around the same profits on a large scale.
A CL win in the near future can give us a commercial boost (especially a convincing win) that would enlarge the size of the club's operating capital (regardless of whether we become more profitable). This can indirectly improve Serie A's TV deal but it wont be enough to keep up with the English growth (from TV/sponsors and commercially from sporting success). Serie A has to tap into the brand potential of the Milanese teams before these brands die and if they do die thats it the EPL will be playing in a league by themselves along with Madrid and Barca (who can be usurped by the british too if they start being shit on the pitch for a long period).
We should pray the Milanese fix their shit quickly and start performing in Europe + pray Agnelli-types take power in the traditionally big clubs + pray EPL types take charge of Serie A + Italian government and economy to become better + pray EPL teams to continue to get things wrong and top coach hirings turn out like LVG consistently.